Composites

[diopter]

I recently began learning to do composites for a project at work.

Made me appreciate how much work and prep and man-hours are needed. Hats off to Ian Robertson.
Doing some research, I found this video and it got me think about one of my single shot long range target rifles, a CIL 950T with a chunk of the toe missing.

 

[quinnbrian]

I've been doing it for 20 years...yes it takes a lot of work...from the plug to the finished part. I've talk to a lot of people..."ya, I've done fiberglass work" they make it sound so easy!! Well it can be, after 5-6 years of doing it 6 days a week but it take skill and knowledge...
Have fun with your project and pm me if you need any help.
Cheers
Brian

 

[cody c]

I've been doing it for 20 years...yes it takes a lot of work...from the plug to the finished part. I've talk to a lot of people..."ya, I've done fiberglass work" they make it sound so easy!! Well it can be, after 5-6 years of doing it 6 days a week but it take skill and knowledge...
Have fun with your project and pm me if you need any help.
Cheers
Brian

I'd like to see/hear more about laying fibre over a reinforced foam structure for making a rifle if you have any thing to share or have some links to short videos.

 

[dero338]

this looks like nice kits anyone selling it in canada?

I'd like to see/hear more about laying fibre over a reinforced foam structure for making a rifle if you have any thing to share or have some links to short videos.

my next stock project is to use this: ht tps://www.boatoutfitters.com/coosa-composites-board for the core

 

[quinnbrian]

Any polyurethane board will work..or even a can of spray foam ( although the spray foam cans are only around 2 pound density). I would like to do something...a little "how to video" maybe when things slow down this winter.
I just picked up a HS carbon fiber stock ,for my Savage model 10 maybe a good candidate to make a mold off of. It all about time...most of my days start at 4:45 am and end at 7:30 pm. I do stop to look at CGN at work or after,but usually not enough down time to do a step by step...but would like to!
Cheers
Brian

 

[diopter]

Thanks for the offers of help, May just need it.
What I'm doing is a Carbon fiber rectangular box to be used as a vacuum chamber.
First attempt was a concave mold with 90° corners, vacuum bagged. It all stuck fast and was a write-off. Mistakenly used Urethane as mold sealer.

1st mold pictures, out of sequence.
https://ibb.co/album/duEZ1F

2nd mold still work in progress. Plug type, red cardboard is for carbon fiber layers template. Sealed with mulitple layers of MGS 335 resin and H335 hardener, sanded to remove resin lumpy high and lows.
Warming up the resin cup in warm water helped to degas the resin. Airtac sprayed onto carbon fiber to prevent unraveling the weave during cutting. What looks like cheap vinyl wood covering is teflon release roll
https://ibb.co/album/dKrHov

 

[quinnbrian]

You've got the right idea, your work looks great. Just a little tweaking and you'll have it.
The stuff to seal the edges is ,Vacuum Bagging Sealant AT-200Y or something like that...

Here is a supplier I have used for years..http://compositescanada.com/ They have every thing you will ever need ..from open molding to vac, or RTM.
Most of the time a 1/4 inch radius is a little too tight for just a vac molding , but with RTM ...resin transfer molding , you can get tighter corner etc..
The MGS Epoxy 285 + Hardener H285/H287 might be a better choice, it doesn't "go off " as quick , the work time with the 285 hardener is 2 to 3 hour, and the 287 is up to 5 hours, giving you time to work the corner in, if need be.
Is there a reason why your building a vac chamber out of carbon fiber? you could uses MDF , something in the 1/2 to 3/4 inch range with good results.
Cheers

 

[45ACPKING]

I am running a hybrid VA-RTM method I developed specifically for molding rifle stocks.
Have you considered silicone products for your mold material? Fast replacing conventional molding methods..... and very suited for the hobbiest if one can wrap thier head around the process. The site quinnbrian mentions is excellent, definatley spend some time on there.
I use both prepreg fiberglass and carbon fiber as well as dry cloth , depending on application and location in the stock body and certainly prepreg in the tight spots. zero fillers and the stocks come out of the mold with a near perfect exterior finish.
Composites can be a real pain in the behind to work with but with proper set up and a good study of todays innovations in molding without an autoclave..... heck a monkey could do it

 

[diopter]

You've got the right idea, your work looks great. Just a little tweaking and you'll have it.
The stuff to seal the edges is ,Vacuum Bagging Sealant AT-200Y or something like that...

Here is a supplier I have used for years..http://compositescanada.com/ They have every thing you will ever need ..from open molding to vac, or RTM.
Most of the time a 1/4 inch radius is a little too tight for just a vac molding , but with RTM ...resin transfer molding , you can get tighter corner etc..
The MGS Epoxy 285 + Hardener H285/H287 might be a better choice, it doesn't "go off " as quick , the work time with the 285 hardener is 2 to 3 hour, and the 287 is up to 5 hours, giving you time to work the corner in, if need be.
Is there a reason why your building a vac chamber out of carbon fiber? you could uses MDF , something in the 1/2 to 3/4 inch range with good results.
Cheers

Weight. It will be mount on a light duty industrial robotic arm to feed copper plates to be imaged for Printed Circuit Boards.

I bought my composites from Canada Composites, JP Pozzo has been very patience with me.
Yes I am using the Airtech AT-200Y sealant tape.

Tempted to look at foam core next time with router cut slots for air passage.

Still at work now making sure vacuum bag is not leaking too badly before going home.

 

[45ACPKING]

I'd like to see/hear more about laying fibre over a reinforced foam structure for making a rifle if you have any thing to share or have some links to short videos.

first would be to mold your foam core sections in a non reactive foam determined by the epoxy product you are wanting to use and also compatability with any pigments if desired.
I use some foam core but not for the whole stock. These sections are held in place inside the final molds after prepreg sections are laid up. I'm using a pretty advanced method for making composite parts and hunting rifle stocks but the processes can be applied to almost any item you want to mold. It's taken me many years and a few courses to figure my method out but maybe one day here I'll do a video walkthru on making your own rifle stock or carbon fiber AR handguard, custom tool grade silicone overmolded AR grip, pistol grip panels for your favorite pistol or whatever.
Don't often see composite projects discussed here and these discussion usually bore the hell out of my wife and dogs so this is cool for me

 

[BigUglyMan]

That kit is really more about tarting an item up than anything else. You're not making a composite anything, you're merely applying a skin to make it look like something it's not (which is lame).

 

[45ACPKING]

That kit is really more about tarting an item up than anything else. You're not making a composite anything, you're merely applying a skin to make it look like something it's not (which is lame).

well..... while i kinda agree..... I kinda don't.
There is some valuable info in that excellent video that can be transfered to making a complete part. With that kit? well probably not but it's a good video for someone wanting to get into laying up carbon fiber.

In my processes, complete finished stocks are removed from the molds to be clear coated and wet sanded, accessories added and shipped out. That is achieved by using prepreg carbon fiber that is pattern cut and laid up in the molds, held under vacuum, ramped up to flow temp, infused with more resin under seperate vacuum and ramped up to cure temperature.

Now, getting that real nice professional carbon fiber finish on the outside can be a problem if the mold releases with any minor flaws in that finish. So the method shown in that video is the professional way to give that ultra awesome blemish free finished carbon fiber look. I don't often get a call for a carbon fiber outer finish but when it is required, that video is pretty spot on.
** I'm not accepting enquiries about my products here, please respect site rules and don't message me with requests, they will be ignored

 

[diopter]

Here is a question I was wondering about.
Say resin cure time is 10 hours.
Should it be removed from mold right away?
What about heat curing, should all parts be heat cured?

 

[45ACPKING]

Heat curing is dependant on the epoxy type you choose. In the video, the products being used are designed for the hobbiest to achieve that result with a room temperature cure. Similar to most epoxy products commonly sold to the handyman or crafts person.
The epoxys I use will not cure to a stable state at room temperature and are extremely sensative to relative humidity. This type of epoxy requires a temperature "ramp up" and ramp down at time intervals. So at 15 to 25 degrees C with a 20% RH in the work space..... the epoxy I am using will remain in a workable state for a very long time tho after a while it becomes unuseable as it will semi cure.
as for mold removal.... once your full cure time is reached, there is no time limit on removal as far as i have discovered but that may be process dependent. I am not a fully encompassed composites pro but I have chosen a specific path to educate myself in for molding stuff.
My molds are multi part molds made of different materials but the actual mold surface that creates the product is industrial grade molding silicon. requires certain prep and maintenance product to keep mold life but otherwise requires zero mold release compounds.
makes vacuum bagging kind of an "old school" method but relies on the same principles.
the days of needing a autoclave to make a rifle stock are over that's for sure.

 

[quinnbrian]

Here is a question I was wondering about.
Say resin cure time is 10 hours.
Should it be removed from mold right away?
What about heat curing, should all parts be heat cured?

Sometimes it makes demolding easier, when the part is a little "green" to remove. The only problem is sometime the parts will distort , as the part comes to it final cure. I pulled green parts for years, easier on the mold...parts are softer...molds are harder ...etc.
But if a high quality parts is needed, then leaving them , in the mold until fully cured will help with distortion. But again depending on the parts being mold ..eg undercuts, number of pieces in the mold( multiply parts molds)...etc, demolding green, sometimes is the only way to remove the parts your making.

Heat curing , eg warming up the molds and or material , being used, will speed up the cure cycle , as will cooling the molds, material , slow down the process .
The only problem you'll have is, to hot....material goes off too quick...gases more, too cold is the big one....not fully cured parts, sometimes leaving soft points.( don't confused this with epoxy that has not been mix enough)
Look at all polyester/vinylester, and epoxies as a chain, with one or more piece missing...the missing pieces being the hardener...whether it's a MEPK used in poly or vinylester or the second part of an epoxy ...know as the hardener side. If you speed up (with heat) the harder will fight to find a spot to "fill" in the chain , There is always more harder available then needed, and that's what creates the heat you feel , when your part is curing.
If your material is too cold, or molds are, too cold, there is no "race" to fill in all the chain links...some will fill in...some will not...retarding your cure.
As a side note, I've had to open the door of my shop, when it been ...like -5 out to try to slow down a cure on a large part before i lost it.

 

[quinnbrian]

Heat curing is dependant on the epoxy type you choose. In the video, the products being used are designed for the hobbiest to achieve that result with a room temperature cure. Similar to most epoxy products commonly sold to the handyman or crafts person.
The epoxys I use will not cure to a stable state at room temperature and are extremely sensative to relative humidity. This type of epoxy requires a temperature "ramp up" and ramp down at time intervals. So at 15 to 25 degrees C with a 20% RH in the work space..... the epoxy I am using will remain in a workable state for a very long time tho after a while it becomes unuseable as it will semi cure.
as for mold removal.... once your full cure time is reached, there is no time limit on removal as far as i have discovered but that may be process dependent. I am not a fully encompassed composites pro but I have chosen a specific path to educate myself in for molding stuff.
My molds are multi part molds made of different materials but the actual mold surface that creates the product is industrial grade molding silicon. requires certain prep and maintenance product to keep mold life but otherwise requires zero mold release compounds.
makes vacuum bagging kind of an "old school" method but relies on the same principles.
the days of needing a autoclave to make a rifle stock are over that's for sure.

Are you uses sheets of silicon or pour in place silicon.

 

[45ACPKING]

Well, my process for making most parts uses a 1/2" thick silicon bladder that seals around a reinforced rigid mold box, trapping all gasses emitted during the cure. This contains inner molds constructed of pour in place silicon with addatives. Allows for a very detailed and rigid reuseable mold and is flexable enough to assist removal of parts. I know what you mean by removing in that last part of the green phase. Using tool grade molding silicone like a mold maxx product green phase releasing is no longer required. I'll check my labels if it's something you are interested in.
I had a guy who makes replica polymer guns for film props show me some silicone molding materials a few years back and advanced versions of some of those products have revolutionized my own part making methods.

There is so much to learn and so many avenues and directions one can go with composites. It's an industry that is just growing exponentially and so many different methods and products to investigate to find what works best to produce the parts you want. What resins are best for what application ect ect. I work with pre made rolls or i lay up my own prepreg material.... or in other words, materials that are pre wetted out with a room temperature stable resin/hardner already mixed to correct ratio. And has a removable no stick outer layer which makes pattern cutting an easy and clean job. Unused sections or unfinished applications can simply be stored in a large deep freeze to extend longevity and to store the materials. In winter this isn't needed hehehe. But a controlled heat phase is required to fully cure the epoxies I am using and to achieve maximum performance life, durability and hardness of the finished parts.

 

[diopter]

Starting to feel like a poor preschooler from the slums at a university lecture. But please don't dumb it down. Great info.
I do have some more questions.

Q1) I find the Carbon fiber cut to size sheet expand once the resin is applied. Normal?

Q2) My corners did not come out as nice as I wanted. Any Suggestions on how to patch them after sanding to get sharp air tight corners?


Q3) I heated my first batch of resin to help it flow. It seems to have gelled much faster than I expected causing the ripples on the top surface.
Should I use a the 50/50 mix of the fast and slow cure rate hardners or just go for the slow one?

Seems Breather layer was pulled by vacuum to the side where the hose was.

The Teflon release is so slick the resin beads on it. Looks like I'll be force to apply resin to the CF before it gets to the mold.
Release was easy once I trimmed it as close to the mold edge as I dared using a Dremel cutting disc and sander. Used tooth picks as wedges between piece and mold.

After trimming with Dremel cutting disc/sanding and release. Inside.

Outside

Inside corner.

 

[45ACPKING]

the only thing i could suggest is possibly add a second vacuum line, one on each end of the part to stop the material slipping? Not sure if that will work but you could try it. Or possible split the vacuum into 4 lines, run them to each corner and inject your resin in the center of the mold?
For mix rates/hardener rates it's dependant on the resin you chose. The supplier should have data for you to use for different mix rates or choosing a different resin.
This is where composites start to differ between processes.

Have you looked into pre-preg carbon fiber ?

I don't want to give the impression I am a total pro at these things haha. I am learning all the time as composites as an industry and tech is expanding in leaps and bounds. I learned to master a process i had to develop by studying other current methods and adapting/tweaking them to the parts i needed to make.

But my whole journey changed when i got my hands on pre-preg materials and finally got my head wrapped around vacuum assisted resin transfer molding . Then I had an epiphany when i travelled to take a short course in using silicon materials for molds and vaccum chambers/bags.
I'm being a bit vague on purpose and I apologize for that. It took me many years to perfect my method and adapt industry methods to my particular needs when it comes to making rifle stocks and other firearm related items.

I would say that overall, you are on the right track. Your part looks pretty good from my seat and I'd say it won't be long before you have it figured out.

 

[diopter]

No problem. This is an R&D project on a shoe string budget. Any advice or comments are welcome.

Shows people what's involved.
I did read the specs on the MGS 335 Resin I'm using and the H335(fast) and H340(slow) hardners.

P.S. Did a test today with the resin cup heated by hot water in a yogurt container. it gelled in under 10 minutes.