How to .. Making a mold ( with pics )

[Yacht Dr.]

Happy Holidays Iboaters ..

Today I would like to share a simple step by step mold/part guide.

Lets get started !

Ok.. so lets say you have a damaged surface like this ..

But its too intricate and time consuming to recreate ..

So lets just make a mold to help us. For this repair we are going to make a part from the other side of the truck tail light bezel and invert it to install on the damaged side.

First is we make sure the mold surface is clean.

We should probably mask off the area that we want to use .. like this ..

Next step is to apply several layers of wax and/or spray a mold release agent like PVA.

We are going to apply Both wax and PVA because of the minor damage of the surface ( we dont want our part to bond ).

Ok.. we are ready for the part making stage ..

Im gonna spray some gelcoat over our prepped surface before glassing. That way I know we will not disrupt our wax. You could brush lightly some resin/gelcoat .. but a few cans of preval sprayers do it more evenly and quickly.

It should look like this ..

 

[Yacht Dr.]

Re: How to .. Making a mold ( with pics )

Next is the fiberglass. Now we can do two things at this point. We can make a Mold OR a Part ! I will explain in further detail below. But its an option that you have to consider at this point. If your making a Part then you have to be very even with your glass layups.

Im gonna use just mat for this part .. Im gonna shred even pieces for this to make it easy to work with. Then start the detailed lamination.

Okies .. so now the glass is cured its time to pop it off. We used PVA which is Water soluble .. use a water hose or squirt bottle with water on the tape edges and gently remove.

After the careful removal of the part/mold we have this ..

At this point we have both a mold and a part. Wash the PVA ( the green stuff ) off of this and you have yourself a Mold. You can make duplicates of this as long as the mold holds up.

Or you can flip it over and use it as a part .. as long as you were carful working with the glass. Only minimal fairing is going to be required in the end finish.

For those that dont know the difference between Parts and Molds ..

A Part is 'what you see'. A usable product that is part of the Final finish.

A Mold is 'what you see inverted' .. meaning the Mold is only used to make Parts. Its useless in and of itself unless you want to make Parts off of it.

At this point we can use this as a Part .. or a Mold.
Because we can flip it over and not have to grind off the gelcoat and minor prep for the install I opted to use it as a part.

Lets just glass that thing in there ..

This is just one way to utilize a Mold/Part/Plug to save you A Lot of time if you have the chance..

Happy holidays Iboats.

YD.

 

[Trooper82]

Re: How to .. Making a mold ( with pics )

Great info YD!

 

[jbcurt00]

Re: How to .. Making a mold ( with pics )

Thanks YD. At least it was on a Century truck

Always helpful to see the steps even if you 'know' how it could be done. Great guide.

Anytime you want to show how to build a cap mold from a 1960 Glastron FireFlite w/ horrible condition gelcoat, you are welcome in my garage anytime 24-7, no notice required!

Have a great rest of the weekend.

 

[Yacht Dr.]

Re: How to .. Making a mold ( with pics )

Great info YD!

Thanks Trooper

Thanks YD. At least it was on a Century truck

Always helpful to see the steps even if you 'know' how it could be done. Great guide.

Anytime you want to show how to build a cap mold from a 1960 Glastron FireFlite w/ horrible condition gelcoat, you are welcome in my garage anytime 24-7, no notice required!

Have a great rest of the weekend.

Thank you jbcurt .. You didnt specify on who is in charge of the BBQ ..

If there are any questions at all in the process please post them up...

If not .. then I would assume that the thread had been posted properly

YD.

 

[Pmccraney]

Re: How to .. Making a mold ( with pics )

Very cool.. Thanks for posting...

 

[a1964rn]

Re: How to .. Making a mold ( with pics )

Thank You for this great information. I'm sure many folks on here will benefit from this thread!

 

[GT1000000]

Re: How to .. Making a mold ( with pics )

This is a fantastic "How To"... should be added to the "How-To's" as a Sticky...Thanks for taking the time to document this very useful procedure...

 

[sphelps]

Re: How to .. Making a mold ( with pics )

Thats good info YD ! But I am slightly confused .:facepalm: On the side that you made the plug/part from it kinda looks like there is a slight angle on the outside vertical corner . If you flip it to use for a part the angle would be backwards . Maybe it,s just the way I,m looking at it . Then again I may just need to get my eyes checked .:facepalm:

 

[GT1000000]

Re: How to .. Making a mold ( with pics )

Thats good info YD ! But I am slightly confused .:facepalm: On the side that you made the plug/part from it kinda looks like there is a slight angle on the outside vertical corner . If you flip it to use for a part the angle would be backwards . Maybe it,s just the way I,m looking at it . Then again I may just need to get my eyes checked .:facepalm:

The only part that gets used is the light cups with enough of a flange left to attach, the rest gets cut off and the curves on the opposite side is formed when the part is glassed in...

If necessary, you could use some temporary backers for the glass made out of wax paper covered cardboard or something similar...

 

[GT1000000]

Re: How to .. Making a mold ( with pics )

Going back and looking at the first set of pics, I noticed that there was enough of the damaged area left to use as the afore mentioned backer to glass into...make sense?

 

[Yacht Dr.]

Re: How to .. Making a mold ( with pics )

Thats good info YD ! But I am slightly confused .:facepalm: On the side that you made the plug/part from it kinda looks like there is a slight angle on the outside vertical corner . If you flip it to use for a part the angle would be backwards . Maybe it,s just the way I,m looking at it . Then again I may just need to get my eyes checked .:facepalm:

As stated below by GT1m that the only thing that I am using is the Part ..

I used it as a Part .. well and a mold to show you how it could have been Inverted with the same part on the other side. Because its inverted and the curves are opposite we could never use this Full mold as the part. But its still usable in the part making .. took me 20 mins to make the part.

But it sure does save some duct tape and wax paper in the process

All We are looking for is a Complex shape that was done there. .. So I took it from the other side. Just to get the shape and levels.

If you try to reconstruct .. it might take days of duct tape and filler .. just saying

The only part that gets used is the light cups with enough of a flange left to attach, the rest gets cut off and the curves on the opposite side is formed when the part is glassed in...

If necessary, you could use some temporary backers for the glass made out of wax paper covered cardboard or something similar...

You got it G1M !

Its just the part that gets used .. use what you can .. parts/time/materials

Your catching on fast.

YD.

 

[Trooper82]

Re: How to .. Making a mold ( with pics )

YD I do have a question...how do you get the csm so fuzzy? I mean it looks like a bunny tail ..

I'm guessing you lay a board or ruler on it and lift up the strips? I'm sure the technique used will come in handy for me today..got lots of edges that need covered...

Edit: I think I figured it out...a wire brush?

 

[Yacht Dr.]

Re: How to .. Making a mold ( with pics )

YD I do have a question...how do you get the csm so fuzzy? I mean it looks like a bunny tail ..

I'm guessing you lay a board or ruler on it and lift up the strips? I'm sure the technique used will come in handy for me today..got lots of edges that need covered...

Edit: I think I figured it out...a wire brush?

I tear it by hand. I made a pile of longer skinny guys for the edges and little 2" circle guys for dabbing in the hard to get spots.

YD.

 

[Trooper82]

Re: How to .. Making a mold ( with pics )

must be a different type of csm than I have...I tried every which way to get it to fray like that...closesty I got was taking a fine wire brush and rubbing it on the table...small strokes...in the end it did not help, was trying to bend the corner on a piece of ply...

 

[Yacht Dr.]

Re: How to .. Making a mold ( with pics )

must be a different type of csm than I have...I tried every which way to get it to fray like that...closesty I got was taking a fine wire brush and rubbing it on the table...small strokes...in the end it did not help, was trying to bend the corner on a piece of ply...

Remember that what your seeing in the pic is a pile of those strips and rounds ..

If you cant just rip your mat and have fray like that .. then I suggest you have old stiff glass.

My mat is Very flexible and Very easy to tear.

Its simple 1.5 oz mat.

YD.

 

[sphelps]

Re: How to .. Making a mold ( with pics )

As stated below by GT1m that the only thing that I am using is the Part ..

I used it as a Part .. well and a mold to show you how it could have been Inverted with the same part on the other side. Because its inverted and the curves are opposite we could never use this Full mold as the part. But its still usable in the part making .. took me 20 mins to make the part.
.

I see now said the blind man ..

 

[Yacht Dr.]

Re: How to .. Making a mold ( with pics )

I see now said the blind man ..

Sorry .. Im a bit tired .. could you explain your post please so I can understand what your asking or telling .

Thanks ..

YD.

 

[jbcurt00]

Re: How to .. Making a mold ( with pics )

YD:

He, SP (the blind guy), can understand & can now 'see' that you had trimmed the part down from it's molded size w/ the curve...

Have a great week

 

[sphelps]

Re: How to .. Making a mold ( with pics )

Yep , what jbc said . I had originally thought that you just flipped and used the whole mold/part for the other side part . I see now you only used the piece that was identical and cut the unusable part out . Do you have a pic of the finished product ? It would be cool to see how it turned out !
Cheers !