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What type of finish should I use on my finished molds & templates?

I saw the following options at the store:

- shellac
- laquer
- polyurethane

Does it matter which one I use?

Also, there are different types:

- gloss
- semi-gloss
- satin
- ...

What do I choose there?

Thanks.

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Music Is Forever

I don't know that it matters too much. I usually use left-overs from the shelf. Others might disagree. My proviso is that I am not making fixtures that will get years of continual use. If I were doing that, I would make them as absolutely fine as I could. But I'm a hobby builder. On plywood molds and fixtures, I usually apply varnish, because I always have some on hand. Sometimes I'll use the aging shellac in the bench bottle so I can dissolve a fresh batch of flakes for the next project. If you make forms out of MDF, it's good to glue size the cut surfaces first (white or yellow glue thinned with water). Once that's dry, apply the finish of your choice. Now let's see what the pros say. I'm pretty sure the best finish will depend on the level of use and length of service you aim to get out of your jig.

I have the following materials available:

MDF boards
Thick Plywood boards
Thin Plywood boards

I am probably going to make a top template out of thin plywood (as opposed to plexiglass ) and the side mold out of the thick plywood (layered and glued). I will probably use the MDF for the Solera.

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Music Is Forever

I just use the shellac I would normally toss, because it isn't "fresh" enough for instruments. I have a storage can for it, and toss the old in there before I mix some new.

That being said, I don't think it makes a real big difference which one you use. I like shellac because it does the job I'm looking for it to do, and it drys very fast.

-Mark

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Pullman, WA

The more I know, the more I know I don't know.

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the polyurethane was the only type that came in a smaller can.

since I am spending so much money on so many supplies (molds, wood, new tools, books, lots more...) I am trying to save every buck I can.

a small can of poly was around $5, while the other types came in larger cans, at around $12.

Is polyurethane ok for these molds or not?

thanks

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Music Is Forever

If I have leftover shellac on the shelf I wipe that on. Otherwise I'll either brush or spray some bullseye shellac from the big box store.

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Jim Hansen

Yep!

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Pullman, WA

The more I know, the more I know I don't know.

trippguitars.com
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poly urethane oil base , when I buy a larger can and water based poly when I purchase the small can . Each one has it/s advantages the oil base IMHO dries harder and tougher . waterbase easier to apply with a foam brush. By the way florentin , do you speak hungarian ?? as your last name means 10 in magyar, cheers ernie

Thank you for all the replies

Ernie, I grew up in Romania, right on the border with Hungary.
I used to speak Hungarian with my friends as I was growing up, but I forgot a lot. We moved to the States in my early teens.
I still understand some.
My mom is cursive in Hungarian still (even though she's 100% Romanian), and my wife is 75% Hungarian. She speaks some.

I almost went to the Budapest Conservatory for my Masters in Classical Guitar, but I could not turn down the offer from DePaul University.

By the way, my last name is pronounced a bit different than Tíz (which I know means ten in Hungarian).
It is pronounced tee-shay.
I don't really know what the origin of the name is, but I do know that my dad's side of the family have been Romanian as far back as we can remember. That's where the name came from.

It is nice to meet you.

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Music Is Forever

I use GitRot, which is a penetrating epoxy available at marine supplies like West Marine,

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=11151&partNumber=105155&langId=-1

It penetrates and seals. I roll it on, let it sink in and wipe it back with a squeegee and get any drips with an alcohol soaked rag. It says its not designed as a clear coat, but it does cure, just takes a little longer because its being spread thinly.

do MDF boards have to be lacquered?
thanks

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Music Is Forever

You guys finish your jigs and templates?
Huh... Something new every day!

Thanks

I went to the same school as truckjohn

Thanks John. I have been working up the courage to ask that same question. I was suddenly feeling like even more of a troglodyte than I do from seeing the finished products of the membership here.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Nope, they sure don't, but it will be more stable, and more resistant to glue or moisture damage.

I always put a couple of coats of shellac on any large/flat MDF jig or form (i.e workboards, solera, radius dishes, etc...), just to make sure they stay flat and true. I don't always bother on a smaller piece.

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Jim Hansen

I am simply trying to follow 'most' of the directions.

I made a side mold out of thin plywood.
As much as I sanded it all around, there are still small bits coming off from time to time.
I was thinking that finishing it with some Shellac might prevent that (?) from happening.

The MDF I am not sure about.
I probably won't apply anything on it.
It is quite alright the way it is.

...

on a different note, I do remember reading in the Bogdanovich book, that applying some kind of lacquer to molds could prevent them from being altered by temperature/humidity changes.

???

Thanks.

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Music Is Forever

thanks Jim, I just saw your post, right after I finished mine.

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Music Is Forever

note that you asked a about lacquer...

My response is more generic. I use shellac.. either whatever I have left on the shelf or spray/can of bullseye from the borg store. It really doesn't matter. All you are trying to do is put on a moisture barrier to protect it a bit.

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Jim Hansen

To those who build molds, jigs and fixtures with MDF: If you want to finish them with something, I recommend applying a glue size to all cut surfaces first. Then apply the finish of your choice. I didn't when I built my first MDF mold, and the darn thing soaked in I don't know how many coats of shellac before it finally sealed. Or...if it's a disposable fixture, just use it and throw it in a corner. To those who will use molds for gluing: Apply something to your mold that can be heavily waxed with paste wax. Open MDF cuts will soak up the wax so much you'll never even know you applied it.

I wouldn't use water based finishes on MDF. It will make the MDF swell.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

cphannah, any type of wood glue?

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Music Is Forever

I'd glue size with white or yellow glue and a little water. Just a light application. Allow it to fully dry and then come back with your varnish, shellac, poly, whatever.

thanks!

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Music Is Forever

Florentin. My family and I come from kosice in slovakia or kassa in hungarian,it/s abt 6km from the hungarian border. My family speaks hungarian, but were taught slovak in school. Am sure that the city you came from in romania, and kosice were all a part of hungary prior to ww 1, After 1920 all the borders were rearranged by the 1920 treaty of triannon. As to molds and templates I typically use whatever happens to be handy , There is another brushable laquer called deft which works well with a brush, My favorite poly varnish is minwax poly oil based fast drying, readily available at homeless depot or Lowes. It dries quickly, easy to apply with bristle or foam brush , dries hard after 3 coats .I don.t sand between coats, and is fairly water resistant,The occasssional glue spill can be easily cleaned off the mold or template.

thanks Ernie!

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Music Is Forever