# Fiberglassing vs Vac-Forming **URL:** \ **Category:** Proton Packs\ **Created:** [March 7, 2006, 8:47pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605 "2006-03-07T20:47:06Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Master\_Taran](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/m/e95f7d/32.png) [@Master\_Taran](https://forum.gbfans.com/u/Master_Taran)\ **Post date:** [March 7, 2006, 8:47pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/1 "2006-03-07T20:47:06Z")
I had an interesting thought recently; has anyone ever tried taking a vac-formed pack shell and then fiberglassing the interior? Most of the time when I hear about fiberglassed packs, the shell was cast from a silicone mold with a fiberglass mothershell (as in Venkman 71’s plans), but couldn’t a vac-formed shell be fiberglassed? To me, it just sounds like it could be simpler than molding & casting a shell to fiberglass, in theory. I mean, 8 out of the 10 pages of V71’s tute describe all the steps up to fiberglassing, but only the last two are actually the fiberglassing part. I would think that if one vac-formed a shell, one would be able to pretty much skip straight to the fiberglassing, since there would be no need to mold & cast a shell. I mean, you wouldn’t have to mess with the silicone, first of all (no spending hours carefully pouring and brushing on layers of silicone, no waiting for it to cure, no having to buy expensive silicone to begin with). You wouln’t need a fiberglass mothershell, since you’d be dealing with a rigid vac-formed shell, rather than a flexible rubber. You wouldn’t need to worry about demolding anything, and you wouldn’t need to buy any 1630/1638 resin, except maybe if you wanted to reinforce/fill in something, since you would already have a plastic shell. All you would need to do would be to take your vac-formed shell, skip straight to page 9 of V71’s plans, go down to where it says “Getting ready to glass the pack,” and start fiberglassing. Since the strength of a fiberglass pack comes from the fiberglass itself (meaning the cloth, resin and mud) rather than the outer 1630 shell (as far as I understand, anyway), a fiberglassed vac-form shell could be just as tough. Does this sound like it would be a useful thing to do? ---
**Author:** ![GBFreek83](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/g/919ad9/32.png) [@GBFreek83](https://forum.gbfans.com/u/GBFreek83)\ **Post date:** [March 7, 2006, 9:12pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/2 "2006-03-07T21:12:18Z")
Hm, an interesting idea, but then again I don’t know anything about fiberglassing heh, seems like a practical idea… ---
**Author:** ![Funkzilla](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/f/8491ac/32.png) [@Funkzilla](https://forum.gbfans.com/u/Funkzilla)\ **Post date:** [March 7, 2006, 9:49pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/3 "2006-03-07T21:49:41Z")
I think there’d be a few problems with this, at least depending on what you’re intent is. The fiberglass resin and cloth would adhere to the styrene vac shell and thus making multiples would be out of the question. You could vac form your master will polyethelyne, to which nothing will stick, but you’d have a hard time keeping all of the parts of the pack true at 90 degrees because polyethylene isn’t all that rigid. The same goes for styrene: you could fiberglass the interior but it would probably lose it’s shape a bit since the fiberglass materials do have some weight to them and cause the shell to warp during the application and curing process. The only way to combat this would be to use thicker sheets of plastic when vac-forming. The problem with this is they’d become harder to vac form and you’d loose a lot of detail in the pack. Which, costs aside, bring us to the reason why people like Venkman 71 fiberglass instead of vacuum form: you preserve all of the details of your master by fiberglass whereas no matter how thin a sheet of plastic you use you’ll always soften the details at least a little bit when vacuum forming. Who knows? Maybe I’m completely wrong. Just my 2 cents, -Eric ---
**Author:** ![Exoray](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/e/d26b3c/32.png) [@Exoray](https://forum.gbfans.com/u/Exoray)\ **Post date:** [March 7, 2006, 11:59pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/4 "2006-03-07T23:59:23Z")
Yes,you can fiberglass the inside of a vac’d shell to make it stronger, as long as caution is taken… Fiberglass resin gets hot when it cures and when the vac’d shell is heated the details will start to soften, warp and deform… So care needs to be taken to keep the heat build up to a minimum while the fiberglass sets… Many fiberglass tubs, showers whirl pools are built this way with a thin acrylic vac’d shell backed with fiberglass… As for using a vac’d shell as a mold (use of LOTS of mold release might allow for removal without destroying the shell) but the end results would be way too soft IMO, ---
**Author:** ![Master\_Taran](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/m/e95f7d/32.png) [@Master\_Taran](https://forum.gbfans.com/u/Master_Taran)\ **Post date:** [March 8, 2006, 1:43am UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/5 "2006-03-08T01:43:16Z")
> [@Funkzilla](#): > > The fiberglass resin and cloth would adhere to the styrene vac shell and thus making multiples would be out of the question. That was the whole point. My idea was to have the fiberglass adhere permanently to the vac-formed shell. As far as duplicates, why couldn’t you? You’d only need to vac-form additional shells to fiberglass. > [@Exoray](#): > > As for using a vac’d shell as a mold (use of LOTS of mold release might allow for removal without destroying the shell) but the end results would be way too soft IMO, Yeah, using a vac-formed shell as a mold doesn’t sound very effective, which is why my idea was to permanently fiberglass the shell. Anyway, as far as the soft details that come with thicker styrene, would it be possible to use thinner styrene, but just be careful with the fiberglassing (as to not warp the shell)? ---
**Author:** ![Funkzilla](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/f/8491ac/32.png) [@Funkzilla](https://forum.gbfans.com/u/Funkzilla)\ **Post date:** [March 8, 2006, 3:03am UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/6 "2006-03-08T03:03:09Z")
> [@Master Taran](#): > > That was the whole point. My idea was to have the fiberglass adhere permanently to the vac-formed shell. As far as duplicates, why couldn’t you? You’d only need to vac-form additional shells to fiberglass. I was trying to be cost effective in the sense that in order to make multiples you’d have to buy more shells from whoever was selling them, unless you have regular access to a vac form setup, in which case, the average person doesn’t. > [@Master Taran](#): > > Anyway, as far as the soft details that come with thicker styrene, would it be possible to use thinner styrene, but just be careful with the fiberglassing (as to not warp the shell)? Oh, it’s possible, it would just be very difficult I imagine. Not only would you have to keep things aligned, but as Exoray mentioned, the process of the fiberglass resin kicking is an exothermic reaction, which could probably bubble and warp the thinner styrene. -Eric ---
**Author:** ![uscm\_buzz](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/u/c6cbf5/32.png) [@uscm\_buzz](https://forum.gbfans.com/u/uscm_buzz)\ **Post date:** [March 8, 2006, 4:39am UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/7 "2006-03-08T04:39:12Z")
yes you can reinforce your vacuformed parts.. which is actually a good idea.. but care has to be taken due to the heating up effect.. now you can do it alot safer using the boat repair fiberglass kits.. it uses epoxy resin that doesnt get hot… and since its reinforement it works fine.. but hey it may not work for everybody.. no harmfull fumes etc.. ---
**Author:** ![Master\_Taran](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/m/e95f7d/32.png) [@Master\_Taran](https://forum.gbfans.com/u/Master_Taran)\ **Post date:** [March 8, 2006, 8:16pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/8 "2006-03-08T20:16:15Z")
How strong are those fiberglass boat kits compared to fiberglassing the usual way? ---
**Author:** ![Inferno](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/i/df705f/32.png) [@Inferno](https://forum.gbfans.com/u/Inferno)\ **Post date:** [March 8, 2006, 10:25pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/9 "2006-03-08T22:25:33Z")
I’m no expert but I dont think there is a difference, I used a fiberglassing kit for repairing body/hull damage on my Iona body and it worked just fine. ---
**Author:** ![Master\_Taran](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/m/e95f7d/32.png) [@Master\_Taran](https://forum.gbfans.com/u/Master_Taran)\ **Post date:** [March 8, 2006, 11:22pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/10 "2006-03-08T23:22:41Z")
I would think there would be at least some difference, at least if what has been said is true about the resin in the repair kits not heating up like usual fiberglass resin ---
**Author:** ![Exoray](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/e/d26b3c/32.png) [@Exoray](https://forum.gbfans.com/u/Exoray)\ **Post date:** [March 9, 2006, 12:07am UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/11 "2006-03-09T00:07:45Z")
> [@](#): > > usual fiberglass resin Not really a “usual” type, there are three common types of fiberglassing resins,Polyester, Epoxy and Vinyl Ester they all have pros and cons and they all give off heat when curing… Generally over the counter you will get Polyester as it’s the cheap run of the mill version… ---
**Author:** ![Ecto96](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/e/919ad9/32.png) [@Ecto96](https://forum.gbfans.com/u/Ecto96)\ **Post date:** [March 9, 2006, 2:38am UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/12 "2006-03-09T02:38:51Z")
Here’s a crazy idea.. Has anyone ever thought about carbon fiber? Or is that too expensive? If you think about it, building a shell out of carbon fiber would make sense, it would be lightest as well as strongest, they make car bodies outta the stuff, the fastest car on earth with a normal engine (281 mph I think) has a body made entirely out of the stuff, and it’s still a very light car for it’s relatively large size. Just thought I’d spring up the idea. ---
**Author:** ![Master\_Taran](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/m/e95f7d/32.png) [@Master\_Taran](https://forum.gbfans.com/u/Master_Taran)\ **Post date:** [March 9, 2006, 3:05am UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/13 "2006-03-09T03:05:47Z")
There are fiberglass car bodies, too. Fiberglass is plenty strong. I’m not sure which is cheaper, though. But, if carbon fiber is indeed more expensive, I see no advantage over fiberglass. ---
**Author:** ![Master\_Taran](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/m/e95f7d/32.png) [@Master\_Taran](https://forum.gbfans.com/u/Master_Taran)\ **Post date:** [March 9, 2006, 5:29pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/14 "2006-03-09T17:29:37Z")
I just thought of something…I know my original idea was to take a vac-formed shell and skip straight to the fiberglassing portion of V71’s plans(including skipping the application of the 1630/1638 resin), but what if you did actually get some 1638/1630 resin, and coated the inside of the shell prior to fiberglassing? Would the heat of the curing fiberglass resin then be absorbed by the layer of 1630, and not damage the vac-formed shell? Or does the 1630 kick out heat as well when curring? ---
**Author:** ![uscm\_buzz](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/u/c6cbf5/32.png) [@uscm\_buzz](https://forum.gbfans.com/u/uscm_buzz)\ **Post date:** [March 9, 2006, 5:47pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/15 "2006-03-09T17:47:03Z")
yea I would like to reinforce some r2 parts ---
**Author:** ![mike304](https://forum.gbfans.com/letter_avatar_proxy/v4/letter/m/f19dbf/32.png) [@mike304](https://forum.gbfans.com/u/mike304)\ **Post date:** [March 9, 2006, 6:28pm UTC](https://forum.gbfans.com/t/fiberglassing-vs-vac-forming/605/16 "2006-03-09T18:28:43Z")
the 1630 resin doesn’t really get all that hot. I would assume it would absorb some of the heat but not all. I would buy two vac shells incase you screw up on one 😉