Author Topic: Finish on pattern  (Read 11893 times)

Offline stevehuckss396

  • Full Member
  • ****
  • Posts: 1554
  • Sterling Heights, MI USA
    • Steve's Miniature Sparkplugs
Finish on pattern
« on: November 24, 2013, 12:23:03 AM »


What kind of finish is best on patterns for casting. I have tried to do a very smooth clear coat but the sand seems to want to stick to it. I try to dust the pattern but the powder won't stick to the pattern either. Would a gray primer work better with a little bit of a rough finish so the parting dust will stick to it.
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline dale

  • Full Member
  • ****
  • Posts: 10
Re: Finish on pattern
« Reply #1 on: November 24, 2013, 01:18:22 AM »
Steve, I just finished my second pattern because my first pattern had the same sand sticking problem. I used enamel, nice smooth and hard. the sand stuck to it like glue! I thought it was the release I used or poor draft angles. I found some old patterns at an antique shop, the pattern finish looked like some type of none glossy dark varnish however I do not know if it was the original finish. I need to do more research. Dale

Offline steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 12697
  • Central Massachusetts, USA
Re: Finish on pattern
« Reply #2 on: November 24, 2013, 01:30:29 AM »
I sanded mine, polyureathaned them, and then painted them.

I would check your parting powder.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline stevehuckss396

  • Full Member
  • ****
  • Posts: 1554
  • Sterling Heights, MI USA
    • Steve's Miniature Sparkplugs
Re: Finish on pattern
« Reply #3 on: November 24, 2013, 01:50:24 AM »
I would check your parting powder.

Heres what I used.


Description:

BCS parting dust (formerly PD-1) is a professional grade parting dust for use with both naturally bonded (clay) and oil bonded (Petro-Bond™) sands. It is manufactured by Asbury Graphite, Inc., and sold to foundries under the trade name "Diamond Parting #4106™". This parting is (almost) silica free. It is a mixture of porous minerals which have been finely ground. It has been formulated to be highly lubricious (marketing talk... means slick) which aids separation of cope / drag halves and pattern removal . This parting will not water proof the sand surface, so steam and gas can escape from the melted metal. This helps reduce surface porosity.

What It Does:

Parting dust coats the surface of a pattern so that the molding sand will not stick to it. This allows the pattern to be drawn from the sand and leave a clean, sharp impression behind.

Parting dust also coats the sand mating surfaces of the flask so the top half (the "cope") and the bottom half (the "drag") don't stick together. This allows the halves to be separated and the pattern removed. This separation line is called the "parting line" thus comes the name of this material: "parting dust".

How To Use It:

Simply load half a cup into an old white sock and you have a handy duster. Apply a fine dusting to parting surfaces of sand mold and patterns. New patterns will benefit from thoroughly applying a coating of parting dust prior to first time use.

Keep the sock and unused parting dust in a tightly sealed can to avoid moisture absorption. (I use an old coffee can!). I figure I use about a tablespoon per mold. At that rate 5 pounds will last a long time!

MSDS & Health Info:
Read and understand the Manufacturers Material Safety Data Sheet , MSDS, for full information about dangers.
The MSDS is available on this site and is shipped with each order.
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline stevehuckss396

  • Full Member
  • ****
  • Posts: 1554
  • Sterling Heights, MI USA
    • Steve's Miniature Sparkplugs
Re: Finish on pattern
« Reply #4 on: November 24, 2013, 02:06:34 AM »
Steve, I just finished my second pattern because my first pattern had the same sand sticking problem. I used enamel, nice smooth and hard. the sand stuck to it like glue! I thought it was the release I used or poor draft angles. I found some old patterns at an antique shop, the pattern finish looked like some type of none glossy dark varnish however I do not know if it was the original finish. I need to do more research. Dale

Hello Dale!

What release do you use?  For the record dont use pam nonstick spray. That experiment did not go good at all.
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline chucketn

  • Full Member
  • ****
  • Posts: 399
  • East TN, USA
Re: Finish on pattern
« Reply #5 on: November 24, 2013, 02:10:48 AM »
I use talcum powder, the real talc stuff. Works for me. I also coat my patterns with polyurethane to seal them, and then cheap spray paint, what ever is on sale at WalMart.

Chuck
« Last Edit: November 24, 2013, 11:35:53 AM by chucketn »

Offline maury

  • Full Member
  • ****
  • Posts: 515
    • Lone Star Engine Works
Re: Finish on pattern
« Reply #6 on: November 24, 2013, 02:24:28 AM »
I assume you have proper draft on the pattern. I find 1.5 deg is ok for petrobond, my foundry wants 2 deg.
I sand the surfaces down to 400 grit, making sure they all feel smothe. THe finish I use is just lacquer. With wood patterns it
takes 2 coats and 3 for the end grain. Sanding with 220 after letting it dry well, then go to 400 on the last sanding.

I use parting compound from BCS, don't know what's in it. Apply using an old sock. Rub in all over the pattern on a new pattern the first time, then just dust a bit on after that.

Hope this helps,
maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline stevehuckss396

  • Full Member
  • ****
  • Posts: 1554
  • Sterling Heights, MI USA
    • Steve's Miniature Sparkplugs
Re: Finish on pattern
« Reply #7 on: November 24, 2013, 02:52:16 AM »
I assume you have proper draft on the pattern. I find 1.5 deg is ok for petrobond, my foundry wants 2 deg.
I sand the surfaces down to 400 grit, making sure they all feel smothe. THe finish I use is just lacquer. With wood patterns it
takes 2 coats and 3 for the end grain. Sanding with 220 after letting it dry well, then go to 400 on the last sanding.

I use parting compound from BCS, don't know what's in it. Apply using an old sock. Rub in all over the pattern on a new pattern the first time, then just dust a bit on after that.

Hope this helps,
maury

I put 2 degrees on everything that isnt round.

So is the final finish a gloss finish or the 400 grit sanded finish
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 12697
  • Central Massachusetts, USA
Re: Finish on pattern
« Reply #8 on: November 24, 2013, 07:10:01 AM »
I assume you have proper draft on the pattern. I find 1.5 deg is ok for petrobond, my foundry wants 2 deg.
I sand the surfaces down to 400 grit, making sure they all feel smothe. THe finish I use is just lacquer. With wood patterns it
takes 2 coats and 3 for the end grain. Sanding with 220 after letting it dry well, then go to 400 on the last sanding.

I use parting compound from BCS, don't know what's in it. Apply using an old sock. Rub in all over the pattern on a new pattern the first time, then just dust a bit on after that.

Hope this helps,
maury




Dave
I put 2 degrees on everything that isnt round.

So is the final finish a gloss finish or the 400 grit sanded finish

That's about the finish I have on my patterns....

"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline stevehuckss396

  • Full Member
  • ****
  • Posts: 1554
  • Sterling Heights, MI USA
    • Steve's Miniature Sparkplugs
Re: Finish on pattern
« Reply #9 on: November 24, 2013, 12:05:29 PM »

That's about the finish I have on my patterns....

The varnish finish or the 400 grit finish?

Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 12697
  • Central Massachusetts, USA
Re: Finish on pattern
« Reply #10 on: November 24, 2013, 12:10:11 PM »
The 400 grit finish.

I sanded to 400, then poly'd it, then painted it
[/URL]

Once I got the pattern there, the foundry guys painted it again the silver color ( a fact I only just remembered)  I seem to remember that this was a special paint...but this was a while ago.   I would try contacting them.   Nashua Foundry, Nashua NH.    Ask for Pete Lyons.



Dave
« Last Edit: November 24, 2013, 12:13:31 PM by steamer »
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline stevehuckss396

  • Full Member
  • ****
  • Posts: 1554
  • Sterling Heights, MI USA
    • Steve's Miniature Sparkplugs
Re: Finish on pattern
« Reply #11 on: November 24, 2013, 05:51:30 PM »
Once I got the pattern there, the foundry guys painted it again the silver color ( a fact I only just remembered)  I seem to remember that this was a special paint...but this was a while ago.   I would try contacting them.   Nashua Foundry, Nashua NH.    Ask for Pete Lyons.


Thanks Dave!

I emailed and have already gotten a responce. He wanted some specific info about what I was talking about. I wrote back with your name and a photo of the pattern hoping that will jog his memory.
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 12697
  • Central Massachusetts, USA
Re: Finish on pattern
« Reply #12 on: November 24, 2013, 06:00:01 PM »
Cool!

Pete treated me really well and was a great help as I was developing those patterns.   Hope he treats you the same.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 12697
  • Central Massachusetts, USA
Re: Finish on pattern
« Reply #13 on: November 24, 2013, 06:24:29 PM »
Use this photo Steve....if he needs his memory jogged.....

"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline dale

  • Full Member
  • ****
  • Posts: 10
Re: Finish on pattern
« Reply #14 on: November 26, 2013, 11:12:14 PM »
Steve, sorry it took so long to reply. I tried common talcum with petrobond. I tried the simple route. still think its my finish on the pattern. Its just an aluminum plaque but AND my first pour but its leaving me thinking there is more to this foundry stuff. However I will figure it out! With help of course! Dale

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal