Jump to content
Fisheveryday

Separating fiberglass molds

Recommended Posts

I've been trying (attempting ) to make some fiberglass 2 piece injection molds , I'm able to get the bottom half  near perfect but when I pour the top I'm not able to get separated without breaking the top half 

Ive tried different thickness of resin, waxing with 4 -5 coats of magiurs , painting the bottom half then waxing , cutting the mold in half with a table saw worked best but was a challenge to get a cut perfect with thin portions of the bait like claws. Any suggestions techniques , release agents available would be appreciated .

 

Dale 

Link to comment
Share on other sites

I have not tried making molds from fiberglass, but I have out of difficult materials like Alumilite Vac-Master 50.  On my silicones and Vac-Master 50, I find a light coat of Petroleum Jelly works well.   Also, most of the problem comes when you try to seperate the molds the first time.  I find that is from the top layer seeping around the edges of the bottom half and bonding to it.  I remove the bottom half from the mold box and coat the edges of the bottom half with the jelly, then put it back into the mold, then coat the bottom half exposed layer, then proceed as normal.

You might try petroleum jelly and see if it works for you.  I also get excellent results from Alumilite's UMR but the jelly is available over the counter (Vaseline and the like).

 

 

Link to comment
Share on other sites

Anglinarcher is right on with his points.... You can try a PLA release film.... it's basically a water based spray on film that will allow you to separate one part from the other when making fiberglass parts.  I used it while making a few motorcycle fenders/molds.  You spray it on - let it dry - layup the other part - then after it cures - use water to dissolve the PLA while trying your best to pull the molds apart.  Even with the PLA stuff - you gotta work it.... most of this stuff is expected to be used on big highly drafted parts - and even those you gotta bang around a bit.... on small things like we use - its tough.

Look up the PLA release film online.... it's not expensive from what I recall... 

 J.

 

  • Like 1
Link to comment
Share on other sites

9 hours ago, Anglinarcher said:

I have not tried making molds from fiberglass, but I have out of difficult materials like Alumilite Vac-Master 50.  On my silicones and Vac-Master 50, I find a light coat of Petroleum Jelly works well.   Also, most of the problem comes when you try to seperate the molds the first time.  I find that is from the top layer seeping around the edges of the bottom half and bonding to it.  I remove the bottom half from the mold box and coat the edges of the bottom half with the jelly, then put it back into the mold, then coat the bottom half exposed layer, then proceed as normal.

You might try petroleum jelly and see if it works for you.  I also get excellent results from Alumilite's UMR but the jelly is available over the counter (Vaseline and the like).

 

I also get excellent results from Alumilites UMR.

9 hours ago, Anglinarcher said:

 

 

Link to comment
Share on other sites

21 hours ago, Fisheveryday said:

Thanks for the advice will pick up a can of the umr ,  appreciate the help have gone through allot of resin and allot of waste, I've got allot of ideas for what I want In a lure but so fare allot of work and no baits lol I didn't want just start buying things Thanks again  Dale 

 

If you don't wanna waste money/time/etc... get a different hobby!!! LOL!!!  Innovation cost money.... no matter if your the most frugal of people - just be prepared to have things go wrong and always buy a little more material/supplies than you THINK you'll need.... you'll need it!! LOL!!

 Good luck!

  J.

 

Link to comment
Share on other sites

I have made resin molds, and find floor wax very effective as a release agent. Be generous with the wax, as the heat generated in the curing process will melt the wax and give you a good contact between the two halves.

I apply a little heat from a gas blow torch to melt the wax, then brush it on with a half inch cheap brush. Try not to burn the house down :)

Dave

Edited by Vodkaman
  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...


×
×
  • Create New...
Top