I’m neww to fiber glassing useing a mold and have alot of questions so here I go…
Project: Fiber glass rifle stocks
Molds: Alum. outer shell with Devcon Flexane as the molding cast.Very nice molds
Mold type: 2 piece split in the middle and bolted together
End product is Hollow and should weigh in @ 1.5lb with reinforcement in key areas
Resion: Fibre Glast Epoxy (20 min)
Glass: 6oz
Problems: voids in small areas,very small and tight angles, resion runs to the bottom of the mold, I have not been using a gel-coat. the molds look as if the owner sprayed on the resion ( the previous owner will not tell me anything about the way he made the stocks)
Is there a type of lite-weight foam I can use to expand in the mold to press the glass and resion into all the small and tight places??? I can post pic’s of the molds and my problems.
I need to get this problem fixed…6k invested in the molds and the wife is not happy nor are my customers that are back logged. Thx in advance
Zane
There are a couple ways you could address this problem. For most of us here, the overall response is probably going to be use either vacuum bagging or infusion. Both will easily address this issue. However, if you wish to continue with wet layup, you might just want to be persistant in pressing the composite into the tight areas. This works for me sometimes, but I would switch to at least vacuum bagging.
Also if you are taking long than 15 minutes close and compress the mold halved together, the resin will already starting to gel and you will get those air pockets as it has stopped flowing.
Try a longer working time resin matrix.
You could make a silicone bladder that you can out into the mold before you close it then add some air pressure on the inside or vacuum om the outside.
Or get the guy you paid the 6k to for the molds to tell you how they work!
What is vacuum bagging or infusion? I see no holes in the molds. Should I use a spray on gel-coat??? The finished stock should weigh 1.5lb
Look in the Tutorials & Articles section for Vacuum Bagging and VIP vacuum Infusion Process.
But is there anyway you can get digital photos to post for us to view what molds you are working with to better help you???
I’m for sure I can help you get the weight down as I’m a Nascar racer and well…:rolleyes:
I’ll have some pic’s later today
Thanks
Zane
Mold Pic’s
1 more mold pic.
Spraying Gel coat into the mold first would be 1st step. let it “B” stage.
Next would be a lamination resin coating (slow curing rate) and laying in the reinforcements (Glass, Carbon Fiber or Kevlar) with 2 or more layers but each cut in a different direction.
I’d then let it cure.
Then maybe cast some silicone rubber as a pressure bladder tool so when you go to make parts, the top half of the mold is bolted on, it will fully compress the laminate together. But it would have to done while the resin is still in a liquid state, so you need a slower rate of curing resin and one that does not need air to cure.
So…use gel coat then …say a 20 min epoxy to lay up then when still tacky use a 102min to seam them together???
Is that a benchrest stock?
What are you using for the inletting?
“Project: Fiber glass rifle stocks”
I know it’s fiberglass, but you can’t just lay layers of fiberglass for the inletting. You can run into a lot of problems with having a hollow core especially for the inletting. Just cranking down on the action screws can crack the stock. What about the rest of the inletting? Is there enough material to be milled away for a recoil lug? Will the action be pillar bedded or will the action be epoxied to the stock?
I have Alum. inserts for round and flat bottom actions for the action area and the barrel channel that bolt to the inside of the top mold. Yes, it’s a BR stock.
It also has pillers installed, no milling is needed, bed the action and it can be eather glued or screwed in
I’m not into guns, so you guys lost me…
Maybe more pictures closer up and what the part looks like after coming out of the mold???
When I built my own stock a while back (pics are in the showcase section), I avoided molding the inletting because it can be a bitch. Even McMillan doesn’t do that.
Does the stock need to be completely hollow, are you going for a certain weight to make the maximum for a particular class? I’m assuming you are having problems with getting the resin to sit flat around the bolt handle cutout. The stock I made, I did it sort of like how McMillan makes their stocks. Gel coat the molds, then lay up the two halves. I let mine cure fully then bolt the two halves and fill the stock. I don’t know how much room you have inside the stock, but what McMillan does is fill the forearm with a mixture of resin, chopped fibers, and a lot of glass beads to keep the weight down. The action area would have less glass beads and more fibers. The buttstock with expanding foam to dampen noise. They adjust the mixture if you are targeting a certain weight class.
If you can do it this way, it would make it easier to fill all the nooks and crannies around the inletting.
Scooter,
I saw your hand guard and grips…WOW they look Great 
Could you tell me what type of resin you used and what gel-coat I should get??? I was told to use Reichhold EPOTUF 37-127 but only can get it in 55 gal. drums (1,400 bucks per drum) and I don’t need that much at 1 time.
I have been using a epoxy and its not working as well as I expected.
As for my issues.you hit the nail on the head!!!
I do have enough room to fill the stock but I need to keep weight down to about 1.5 lbs or 1.6
Your last post has realy helped me out.
Apply the gel coat, lay up the glass and let cure ( do I add resin at this time?)
and then apply resin to both parts and bolt together. Do I rough up the 2 maiting parts with a file or sand paper??? Aas you can see I have alot of questions. If you would e-mail me at zanea10@bellsouth.net with your
phone # and a time to call
Thanks
Zane