whats the colored please coating on a f/g mold

im currently designing an aluminum instrument / control console for project in the design phase,.. I work with aluminum but would like to learn more about f/g mold making to have more manufacturing options available for marrying some f/g components to the aluminum boat as aluminum can be time consuming & I think a mixture 0f the 2 may be a good soloution to speed manufacture of smaller more decorative parts for me ( bezels ,trim rings,etc)..I`ve made mold parts before from wood & metals,but never carried out the final steps as in those cases I was just acting as a designer from strictly an esthetic standpoint from a f/g contractor I know a good bit about it ( to keep negative draft ,bracing techniques etc.) but don't know what the final steps are after the mold piece is finished from an esthetic point of view ... does anybody know what the (usually) red surface that coats the mold piece is called ,& if so will you tell me about it..thanks in advance

 

Its "just" gel coat. Usually red as that is a strong contrasting colour and not many boats use it. Black is another popular colour, I like orange. However, usually the mould is finished with two coats of gelcoat. The outer one is actually a clear gelcoat, as it's harder than pigmented ones

Richard Woods

 

It's called 'tooling' gel coat with different properties than regular molding gel coat. It's harder and more brittle because of fillers that give it dimensional stability. It tolerates higher heat and polishes to a higher gloss with more durability. It resists solvents better. It comes mainly in black and bright orange and sometimes green. It is best if the mold color is a contrast to the the color of molded parts, as that helps in getting the correct coverage of the regular gel coat in a mold when making moldings.

 

how bout applying it?..i hear gel coat`s "shot" on..& depth & depth consistency is measured with that little notched tool...is it shot on with a specialty sprayer?...& does it dry on its own ..I ask because I`ve heard gel coat only dries in the ABSENCE of air,& may have to be covered with something when you shoot the plug with the tooling gel coat

 

You can spray it or brush or roll it

You are correct that gelcoat stays tacky when exposed to air, that's so the layers of glass/resin bond to it. However there is an additive that allows the gel to cure in air which you use when "flowcoating" ie gel coating the outside of the laminate. Normally of course the gel coat goes on the mould and is then covered with fibreglass

Applying gelcoat is a special skill as it is easy to be "shy" and thus end up with grey/black patches in the final product. By that time there is nothing you can do as you don't know until you have finished and released the moulding. You can also easily get wrinkles or "orange peeling"

Richard Woods

 

I think one of us may be misunderstanding the other guy ..& it may be me ?? this would be "tooling" gel coat applied to a "plug".. not to produce a product, but to create a MOULD to produce a product so I wouldn't be releasing a mould , but MAKING a mould..i have plenty of experience spraying & finishing paints,& this seems kinda like that.. I assume if I get any orange peel I can wetsand & wheel to a finish with compounds just like painting but obviously following the rules for spraying gel coat,THEN I would be spraying or mopping my release ,gelcoating & glassing ...am i wrong? ...& either way,now I guess I know a problem I may experience after I make the mould ( orange peel ,being shy,grey patches etc),

 

Apart from using tooling gelcoat and not worrying so much about weight, there isn't really any difference between making a mould on a plug and making a moulding on a mould, at least as far as gelcoating is concerned.

Remember it's a mirror image, so hollows become ridges and vice versa. Usually it is better to try for a fair plug rather than expect to fair the mould, although you will spend some time polishing and waxing whatever you do. I usually use release agent on the first couple of pulls just to be safe.

As a rough guide you probably need twice the layup on a mould as on the moulding.

Richard Woods

 

would you ( or anybody) NOT use a release agent at ANY time ?..I`ve used spray releases & wax type releases but I`ve never NOT used a release...is it common practice to not use a release after a few pulls ?...maybe if the part pulls off real easy you may elect to skip the release step ?...I ask out of sheer ignorance & because the little bit of f/g moulding I`ve done has always received a release coat before anything got done & I thought it was an absoloute necessity

 

Sorry, I confused you. I meant a pva liquid release agent, rather than a wax one, which you would normally use as it polishes better

Richard Woods