Coating options for short run mdf mould

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Coating options for short run mdf mould

Author	Message
dbcrx	dbcrx posted 10 Years Ago HOT Topic Details
Group: Forum Members Posts: 46, Visits: 1.2K	I'm working on specing/quoting for a job and I'm trying to decide the best way to make the mould. As usual, it has to be as cheap as possible. The job is to make 4-6 (maybe more later) simple rectangle crates - 5 sided, open top (or to be closed just with a bit of ply or flat sheet) gel coat finish on the outside. The finish doesn't have to be great as they're only for floating a pontoon on, I just need enough of a finish to ensure easy releases. I will probably just make a simple mdf female mould for this. I just need to decide on the best way to seal it. As I said it will only need to handle half a dozen pulls, so what do you think. My choices are down to epoxy coating resin, epoxy tooling gel coat, both of the previous, pattern coat gloss, or (as I'll be buying it anyway for the parts) would polyester resin do the job?
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Hanaldo	Hanaldo posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	I would use something easier to sand if it was me. Duratec surface primer is made for the job, polishes to a high gloss, and will give you an easy release. BUT, if I were trying to do it as cheap as possible, I would use a single pack acrylic primer filler to seal the mdf. Sand it down flat with 400/600 depending on how much flatting it needs, then leave it at that. Then spray it with PVA and make your part off that, polish it up. Easy and cheap, wouldn't cost more than 50 bucks to make the mould. Would last for a few pulls as long as you aren't ripping at the mdf to get the part off it. Alternatively, you could use epoxy or polyester resin, as you said. Throw some microballoons in there to reduce the density and make it easy to sand, but it won't polish up. You COULD simply use general purpose laminating epoxy or polyester, but to me that doesn't sound like a cheap way of doing things because of the labour involved in sanding it down.
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Brian_s	Brian_s posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 99, Visits: 2.5K	You could use Melamine faced chipboard. Resins do not stick to it. Although I normally use a wax or PVA coat to make sure. Brian.
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*VVS*	*VVS* posted 10 Years Ago HOT Post Details
Group: Moderators Posts: 226, Visits: 334	Why not come at it from a different angle, get some polypropylene board and make each side and the bottom, make it so it comes apart with wooden batons as a frame then fillet the joints with plastercene (unsure of spelling) and bobs ya auntie, 100% safe that you will get a release.
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