interestedparty
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| posted on 21/1/11 at 09:41 AM |
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Preparing MDF plug for mould making?
I want to try making a panel, and I think I could most easily make a plug from MDF. HAving done that I then will need to get a surface which is both
smooth and sealed. I have heard that it is possible to paint MDF with 2K primer using a brush (which I understand is safer than spraying although more
sanding will be needed).
Does anyone have any expperience of this, or have other suggestions?
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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smart51
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| posted on 21/1/11 at 09:57 AM |
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I've used polyurethane varnish on MDF to make a releasable surface. You need a couple of coats as the first one just sinks in. Remember NOT to
use water based varnish as it makes the MDF swell. It doesn't give a very smooth surface so several coats with sanding in between will probably
be needed.
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balidey
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| posted on 21/1/11 at 10:07 AM |
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Best stuff I have used for this purpose on MDF is melamine paint, got it from B&Q I think. Meant for kitchens, but it is probably the best paint I
have used on MDF.
Dutch bears have terrible skin due to their clogged paws
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kendo
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| posted on 21/1/11 at 10:17 AM |
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We used to coat the mdf with poly resin to seal the surface. Then de-nib and paint with a high build primer called lesanol.
The key thing is that it needs to be dry sanded and then polished.
Once you've got a nice shiny pattern you do the normal mould prep stuff, PVA and wax.
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Neville Jones
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| posted on 21/1/11 at 10:29 AM |
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I've released from straight bare mdf in the past, and probably will again.
Trick is to use plenty of wax, and let it harden properly between coats.
Hard investment casting wax(because that is what I have in stock) is good for the furry ends, other hard waxes would do the job.
Cheers,
Nev.
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Wadders
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| posted on 21/1/11 at 11:15 AM |
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Not done it in the context your talking about, but if you paint it with pink oil based wood primer using a brush or foam roller
and nib it with fine wire wool between coats, the finish is superb.
Al.
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myke pocock
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| posted on 21/1/11 at 12:08 PM |
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The big problem with MDF if you are laminating it into a block is that the surface of the MDF is harder than the core. Consequently when you shape it
and sand smooth it tends to show up the faces as lines where it has been glued together. We used to make vac forming moulds like that for students and
it wouls show up when moulded but it usually didnt wory them. You would need to cover the surface with some form of body filler and then sand
smooth.etc.
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