First try at making and using a match plate

Discussion in 'Pattern making' started by Tobho Mott, Sep 11, 2019.

  1. Tobho Mott

    Tobho Mott Silver Banner Member

    I got it into my head to try casting some flask alignment brackets, and since I figure I'll need a set for every flask I end up making, this seemed like a good time to try mounting my patterns on a match plate.

    I had more pix, but I had to reformat my phone's memory card when it got somehow corrupted, so here's what's left...

    First, the reason why I hate using spray cans. 2 layers of red went down fine, but the gloss sealer I used next just crazed and crackled like mad. I don't know if the red paint wasn't quite all the way dry, or maybe I was too heavy handed with the gloss? Neither would suprise me, I get spray paint wrong pretty much every time. Maybe I ought to buy some sort of brush-on shiny smooth goo for jobs like this...

    This pic is after sanding the worst of it back off, but you can still see the crazy unintended texture I ended up getting, which might have looked kind of nice if it was on, say, the background for a plaque or something:

    PhotoPictureResizer_190910_073951423_crop_505x527.jpg

    And here's the result of a test mold I rammed up. After removing the match plate I dusted the drag generously, then set the cope back down to get a print of the drag on it. You can see that the sprue and the runner in the drag did in fact align correctly! A small victory?

    PhotoPictureResizer_190910_110602619_crop_775x602.jpg

    I think the broken sand on one side can be blamed on my uneven lifting of the cope more than on the patterns themselves - some sand got in between one alignment pin and its bracket, so that side of the flask did not want to let the cope lift with the other. Next time I'll put an upside down cup over it, or use some compressed air to blow sand out of the alignment hardware maybe. I don't think I rammed too hard in between the fins, (too soft, possibly) as my sand rammer won't even fit between them, so I just used my fingers to pack the sand in there and tried to do it so it seemed reasonably tight but not super tight. <Shrug>. Maybe I need to set a drywall screw in the sand between the fins to strengthen it so it pulls out easier in one piece...

    Any of you guys ever have a problem with that happening? The paint job I mean. If so, how are you preventing it?

    Oh, and I'm more than happy to receive your suggestions for avoiding the broken sand thing, and the sand jamming up in the alignment hardware too of course! But those things haven't been plaguing me for years like my spray can ineptitude has... :mad:

    Jeff
     
  2. Tobho Mott

    Tobho Mott Silver Banner Member

    Restored another pic...

    IMG-20190906-WA0001.jpg

    Jeff
     
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  3. Jason

    Jason Silver Banner Member

    I'm the spray can king.:p RTF instructions. Multiple thin coats. Slow and steady and check that your clear coat was compatible with your paint. Always shake well for at least 1 minute and be mindful of the airtemp when you spray. Paint hates cold temps and humidity.;)
     
  4. Is there any draft on those 8 half round parts that stick out?, they look like sheer vertical sides in the photo.
     
  5. PatJ

    PatJ Silver Banner Member

    I saw someone (I forget who) make a matchplate not too long ago (or maybe a while back; memory is not too good these days).
    But anyway, they used a solid pattern, rammed it in the standard fashion, and then used a spacer between the cope and drag.

    Maybe I am late to the ballgame.
    Is that how everyone does it? or did I learn something new with using a solid pattern?
    But the idea is to eliminate any mis-match that could occur by trying to attach separate parts of a split pattern to opposite sides of a board or plate.

    Jeff- Your matchplate looks good. I need to try making one some day.
    .
     
  6. FishbonzWV

    FishbonzWV Silver Banner Member

    Wow, double tabs for the pins, that's stepping up.
    I've had the crazing with paint a few times, sure pisses you off after putting all the work into a pattern.
    Usually the instructions say to re-coat in 20 minutes or after 48 hours. I've left it for a week and still had the wrinkles.
    Now I pop them into my powder coating oven and bake them for an hour @ 200 F.
    I also 'polish' my paint with my dry fingers, it's amazing how smooth it gets with a good rubbing.
     
  7. rocco

    rocco Copper

    I'm pretty sure this isn't what you were referring to but HERE is a write up on that technique.
     
  8. Tobho Mott

    Tobho Mott Silver Banner Member

    Mr. Pete on YouTube has a series on casting a match plate, but I like OddDuck's EZ match technique from an old AA thread, which lets you cast the plate in the same size flask it will be used in. Just figured I'd try a simple wood plate this time. The fins do have draft, and I copied the idea of having two of them on each bracket from the ones I saw in one of YouTuber Soat Mon's videos. One each sure would have been easier to demold!

    Spray paint... I do try to use thin coats. But I'm always like, oh, that's a bit too thin, I missed that spot there... Then another, and another, soon the whole piece is dripping. Gets me every time, and no matter how many times I try I don't get any better at it. I think maybe I'll just try and learn to love that crackled crazed finish, should be easier that learning how to use a spray can right. :rolleyes:

    Jeff
     
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  9. Petee716

    Petee716 Silver Banner Member

    I usually give one coat of automotive primer and smooth sanding. Then the pattern gets a good rubdown with graphite. Even if some of the paint is sanded off, as long as there's no rough spots I call it done.
    Were you able to rap the matchplate before lifting the cope?

    Pete
     
  10. PatJ

    PatJ Silver Banner Member

    I recall seeing that post quite a few years ago, and at the time my foundry knowledge was quite fuzzy and new, so I don't think I knew exactly what I was looking at.
    But yes that is the method I was referring to. That is a good write-up about how to do it.

    As I recall I saw Clarke (Windyhill Foundry) use that method about a month ago when I visited his foundry.
    I almost stole one of those kittens (shown in the "Cast Iron Athol Sign" video).
    He had about four running around.

    But after watching the video, that is not the method Clarke uses, so perhaps it was the write-up that rocco mentioned.

    Edit:
    I found it.
    Here is the video I was thinking of for making a matchplate.



    .
     
    Last edited: Sep 11, 2019
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  11. HT1

    HT1 Silver

    the only pattern finish I use is Automotive sandable primer

    https://www.autobarn.net/duplicolor-sandable-primer.html
    pick the color that is most opposite of your sand and pattern base the Red is My go to, just give it a quick coat wait 30 Minutes , then it gets steel wooled start 0 or 00 if it needs another coat of primer , hit it when that is dry steel wool it again, if it is smoothe enough , steel wool it with your finest steel wool 0000 using graphite powder . get into every crease and crevice well with the Graphite, the Black graphite contrasts well with the red primer . I have NEVER had a paint issue using this method . if you have to do a repair clean as much of the graphite off as you can LP air, then a Tack Cloth, you can paint over the Graphite . remember the Pait is filling in detail so go easy

    Couple of other little tricks if your Matchplate is Plywood, it needs to be sanded (orbital sander) and Shellaced to seal it, and yes I use the Rattle cans, dries quickly, if your surface is piss poor( cheap Plywood) , before shellacing it , use a drywall Knife to coat it with wood filler . this will probably need 8 hours to dry , then sand and finish as above. poor surface on Matchplates can cause fins around your casting . warped match plates will totally cerfucker yah, matchplates are best stored hanging , or in a slotted rack upright . see the dividers in the pic below, that would be your matchplates

    V/r HT1

    [​IMG]
     
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  12. Jason

    Jason Silver Banner Member

    Not sure if this would work for you guys, but I have done miles of crown molding. I discovered the best way to fill nail marks and dents and dings on pine is actually to use premixed spackling mud. It dries wicked fast and sands babysass smooth. You will not see how I nail up crown no matter how hard you look. I would try it on your patterns.
     
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  13. Tobho Mott

    Tobho Mott Silver Banner Member

    Great tips guys, thanks!

    Jeff
     
  14. rocco

    rocco Copper

    I like using Bondo, it sets up fast, it's not brittle like spackle, very easy to shape with a sharp knife when it's half set and sands beautifully when fully set.
    FFIW, I have a long thread on AA about a match plate I made about 10 years ago unfortunately my photo hosting service went dark so all of the pictures are down rendering the thread pretty much useless.
     
  15. Tobho Mott

    Tobho Mott Silver Banner Member

    I think I remember that one Rocco, thanks for the reminder. I'll see if I can find it again.

    Jeff
     
  16. Tobho Mott

    Tobho Mott Silver Banner Member

    Petee - yes I did rap the match plate. Maybe not enough, though I'm blaming the broken sand on an uneven lift. Mostly I just wanted to verify the sprue to runner alignment that time anyhow (I'll never admit otherwise :D). Dusting the drag to take a print of it on the cope seemed to be a great way to confirm this.

    The drag was easier by far to demold, I'll do that first next time, to expose more rappable surface for losening up the cope.

    Jeff
     
  17. rocco

    rocco Copper

    I'll save the trouble: Match plate gating
     
  18. Tobho Mott

    Tobho Mott Silver Banner Member

    Thanks again.

    I got the match plate to pull pretty clean today. Still don't have any graphite powder but I rubbed it with parting for now and this time I pulled off the drag first so I could rap on the bottom of the match plate the help loosen the fins in the cope. The downside was not having the pins there to help me lift the plate off the cope. But it seemed to work ok, just a tiny little bit of sand broke off in a couple of the fillets.

    Casting came out nice, all 4 are usable.

    20190915_010321.jpg

    20190915_010336.jpg

    I did forget to radius the inside corner of the sprue to runner transition. And I had to put the pouring basin in the middle of the mold because I didn't leave enough space when I glued the patterns to the board to avoid having it interfere with the fins if I had put near the edge of the mold like I usually try to. This flask is cooked anyhow, I might build a taller cope when I replace it, then it won't be a problem.

    20190915_010401.jpg

    The whole casting came out really nice and smooth, except the surge trap, which is sandpapery rough on its upper half.

    20190915_010416.jpg

    20190915_010442.jpg

    A little bit of shrink near the inside base of one fin each on the pair of brackets farthest from the sprue, but I don't think it will affect their function. I'll try to remember to add a riser next time.

    20190915_010456.jpg

    20190915_010539.jpg

    The texture of my crappy paint job came out pretty good in wheelium! I actually kind of like the way it looks. :D

    PhotoPictureResizer_190915_010835099_crop_1360x1080.jpg

    Jeff
     
    Last edited: Sep 14, 2019
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  19. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Those look good Jeff.

    Let's call that the "Krinkle" finish.......folks actually pay more that!

    Best,
    Kelly
     
  20. Tobho Mott

    Tobho Mott Silver Banner Member

    Lol, now watch me try to recreate it next time and end up with glassy smooth...

    Jeff

    Edit - another pic.

    20190915_113640.jpg
     
    Last edited: Sep 15, 2019 at 8:39 AM

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