moulds

[chev z]

Whats the best and / or cheapest method of taking moulds of existing fiberglass panels.

How much approx. would it set me back to get 2 rear guards and 2  i.e. left and right guards done

 

Your knowledge would be appreciated...Steve

[Six_Shooter]

First off it's "molds" or "mold", no "u", mould with a u is something different. lol.

 

If these will be one time use molds, you can make them just using fibreglass resin and chopped mat. Just make sure you put a release agent like wax and/or PVA. Add at least 3 layers. Release the mold from the panel you are taking a mold of, then, clamp it back on. The reason you release it and then clamp it back on is so that after the next step you will be able to get it back off the part you want to replicate. At this point use some material, to make a frame work to re-enforce the mold. There are a few techniques that can be used. For production molds and even some one time use molds, I have used plywood to create a frame work around the perimeter of the mold. Another technique I have used was to use copper pipe insulation that was cut in half, cardboard rolls, similar to what is used for paper towel or toilet paper cut in half also works well. With the wood technique you only need to bond the wood to the mold, with some fibreglass to create a stiff mold. Using the pipe insulation or cardboard tube technique you need to completely 'glass over the pieces added. This techniques relies on the added fibreglass to add the strength, after that has cured what you used to create that shape adds no structural value to the mold, it's just there to create a shape for the glass to use while curing.

 

If this is your first time getting into using fibreglass, I strongly suggest starting with something smaller, to get a feel for the working time and mixture ratios before you try to mix up enough resin to create a mold for a large panel, which by the way, will usually be mixed up in smaller batches as you use them up, using new containers for each batch. The little bit of already curing resin can cause issues when you try to mix a new batch in that same container. Once the resin completly cures though, you can break out the hardened resin and re-use that container, provided it is a re-usable type. I like to use windshield washer fluid containers, like you would buy in the store, with one large flat side cut out. You also have a handle this way too.

 

There's lots more to it, but that's some of the basics.

[PeterAllen]

First off it's "molds" or "mold", no "u", mould with a u is something different...

 

We speak and write the Queen's English down here, it's "mould", not some American bastardisation... Ewes Canucks should no that!

 

 

Thanks - Good fibreglassing information. I'm about to start some serious fibreglassing and I wonder if you could explain if the wax is primarily to smooth off the surface of the 'buck' and a PVA release agent should always be used, or, is it an alternative release agent? Thanks.

[chev z]

Interesting how Canadians hate the French and Yanks but use their languages...lol

Then I suppose we don't like the Poms much , especially with the ASHES series upon us

 

Thanks for the info ...six shooter

 

Advise to all Canadians in avoiding terminal injury;

 

Foot should be removed from mouth, before shooting oneself in foot

 

LOL

 

 

[Six_Shooter]

No, in regards to a mold for copying an object, mold without the u is correct, mould with the "u "is what grows on left over pizza from the previous night's party. Trust me, I'm all about the "u"s in everything, including colour, and other words that aren't coming to me currently.

 

Anyway...

 

The wax does help fill in those small imperfections, but it is mostly to make the surface more "slick" to release the mold from the object you are copying, or buck. I don't always use the term buck, because I use it in very specific cases, but that's beside the point. The PVA is pretty much always used. The only exception is when you get a well seasoned mold, then the parts will release easier. This is likely due to a build up of wax and PVA that never quite gets washed or buffed away, but also likely due to some chemical changes with the heat created by curing resin. I would still prefer to use the PVA anyway, it's pretty cheap anyway, considering the alternative of having your part get stuck to the mold and then starting from scratch.

 

One of the biggest things that will help with releasing the part from the mold is getting the correct draft when making the mold, here is where choosing how to place the mold on the buck, and how it will release is important. Sometimes when making the buck, adding some Plasticine, or modelers clay to add draft to the buck can help a lot.

 

Then when you get to actually releasing the part, you will think you're breaking either the part or the mold, you will hear some pretty nasty cracking sounds as the part separates from the mold, this is heart wrenching the first few times you hear it, then after a while you get used to the sounds and start to learn how much of a separation there is by the intensity of the crack and the tone. You can buy some plastic wedges to help this go more smoothly too. I know my local-ish fiberglass supplier (about an hour and a half away) sold wedges of different shapes and sizes to get the part and mold separated.

PVA is also water soluble, so sometimes using warm water poured between the mold and part will also help separate them.

 

If you're looking to make production molds, don't skimp on the gel coat for this, get the tooling gel coat, it stands up to a lot more use than gel coat used to make the parts themselves.

[NZeder]

We speak and write the Queen's English down here, it's "mould", not some American bastardisation...!

I concur it is mould not mold in this part of the world. Mould(1) and Mould(2) is how we spell it for the two meanings. Mould(1) = to make a shape from a substance and Mould(2) = green/growth etc

 

And I back this up with the Oxford English Dictionary I have here in print at home and also online with the Cambridge Dictionary see http://dictionary.cambridge.org/dictionary/british/mould_2

[Scoota G]

Dale had a "mold" made of his front spoiler and that cost $120 i think.

[Six_Shooter]

Ok, so you're just looking to modify the existing part, or modify the existing part then make a mold to create a completely new second part, that has the modifications?

 

If you're just looking to modify it then it's a different ball of wax.

[chev z]

NO , I am not modifying the existing guards , I would like an exact mould of them .They are the IMSA wide body guards / flares

They are to be fitted to my race car , considering the cost/ frieght from the USA  , I really need to have some backup insurance if I happen to damage them.

 

Otherwise wife might deport me ...probably to Yankie land where I would have to learn a different language

[PeterAllen]

Apologies for hijacking the thread.

 

six-shooter - I'll contact you via PM.

[NZeder]

Back on topic good idea - enough of the creping mould stuff 

 

Have you thought about contacting the guys at Alfa Fibreglass in VIC - they seem to have a few zed moulds/products for sale so they would be the best to give you an idea on the costs etc

 

see http://www.motorsportfibreglass.com.au/index.php