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3 examples of wood foundry patterns #1: Can you tell what the white pattern is?

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Blog entry by Patternguy posted 02-24-2017 03:01 AM 6039 reads 0 times favorited 39 comments Add to Favorites Watch
no previous part Part 1 of 3 examples of wood foundry patterns series no next part

Three different patterns.

This pattern makes 2 iron fittings for every core put in the mold.

Need to hold up a handrail?

This is a great example of well-planned, smooth parting lines perfectly splitting a pattern in two!

Look at this one closely and try thinking of where you’ve seen this shape before.

Clue?...wet hands and no paper towels:)

This pattern was made about 28 years ago, and is made of mahogany. The walls are a uniform .200 +/- .015 thick. The customer was afraid the wood grain would show up on the casting and asked us to seal it with automotive paint before the production tooling was made.

This one was a real challenge to stay within tolerance, the drawing was a bunch of section views.
I think I might have spent as much time on the follow block as on the pattern.



39 comments so far

View Kelster58's profile

Kelster58

670 posts in 686 days


#1 posted 02-24-2017 10:16 AM

A pattern for a thin wall casting made from wood. That takes real craftsmanship. Looks like a part for a farm tractor.

-- K. Stone “Tell me and I forget, teach me and I may remember, involve me and I learn.” ― Benjamin Franklin

View Kaleb the Swede's profile

Kaleb the Swede

1861 posts in 2115 days


#2 posted 02-24-2017 03:52 PM

Very neat. I never thought these things were cast this way. Guess I should have known. Thanks again

-- Just trying to build something beautiful

View Don Broussard's profile

Don Broussard

3665 posts in 2397 days


#3 posted 02-24-2017 08:04 PM

Hand dryer mold. Very tight work too.

-- People say I hammer like lightning. It's not that I'm fast -- it's that I never hit the same place twice!

View Patternguy's profile

Patternguy

66 posts in 837 days


#4 posted 02-24-2017 11:09 PM

Yep…sold by World Dryer inc.and found in restrooms everywhere.
I enjoyed every minute of building this one. At that time, you needed a master pattern in order to build production tooling. Wood was still king, as well as the pattern makers hands to work it.

This pattern was used to make a set of urethane, vertically-parted, production tools. In this case, one 1.25” iron plate with the outside shape molded on top of it. And a 2nd plate (actually it was an 8” thick block) with a pocket in the shape of the inside of the pattern, cast into the block.

Patterns always went back to the customer. I don’t recall why, but the tooling was delivered and the pattern sat on the corner of my layout table for weeks. One day I threw it under my work bench where it sat for years.

I brought it home one day for show and tell because I thought it is so recognizable.

I still think of it every time I hit the button somewhere to dry my hands.

View PimentelEng's profile

PimentelEng

22 posts in 26 days


#5 posted 09-23-2018 10:54 PM

Patternguy. Im new to pattern making,not by choice. Due to a disability i wont get hired anywhere,so i had to choose a way to make money using skill I already had. Im geared towards classic cars. Would you be willing to share some of you knowledge. Im also new to working with mahogany and my only tools are my table saw and some chisels. I shape everything by hand,where my sculpting skills come in. I also own a 12in pattern makers ruler for aluminium.
My first pattern made from MDF,its hell to work with,very unstable.

View PimentelEng's profile

PimentelEng

22 posts in 26 days


#6 posted 09-23-2018 10:59 PM

Im in the process of making another valve cover pattern but ive come to a blockade. I feel like giving up

View Patternguy's profile

Patternguy

66 posts in 837 days


#7 posted 09-24-2018 03:15 AM

I remember the days of my apprenticeship, I felt the same. But the 1st rule of life, and patternmaking is never give up.
If you need some guidance i’d Be happy to give you my 2 cents.

View jbay's profile

jbay

2677 posts in 1045 days


#8 posted 09-24-2018 03:26 AM

Can you tell what the white pattern is?

It’s a cover for an 8-Track cassette player,
just need to cut out the whole for the 8 tracks and put in the speakers. :)

View PimentelEng's profile

PimentelEng

22 posts in 26 days


#9 posted 09-25-2018 07:09 AM

Lol. 8 tracks,I still play records on my 1946 Newcomb. Its 33in long and its a finned valve cover for the pre 53 Buick straight eight.


Can you tell what the white pattern is?

It s a cover for an 8-Track cassette player,
just need to cut out the whole for the 8 tracks and put in the speakers. :)

- jbay


View PimentelEng's profile

PimentelEng

22 posts in 26 days


#10 posted 09-25-2018 07:39 AM

Im stuck here. I’ve looked over dozens and dozens of mahogany patterns but im still confused. Im trying to come up with similar patterns as pictured. How can i go bouts doing it my self. I can only find mahogany in thicknes of 3/4 so carving them out of a block is out the picture.

Im trying to make one piece patterns as shown with roughtly 1/4 in wallls at about 5” height by 4.5” wide and 21-1/4 long. My first thought was to start of with a hollow box made from 3/4” sheets and shape it from that,but im not sure. My second option was to laminate sheep and carve it from that. I dont know. Im good at sculpting and carving but still new at wood working.
One thing i noticed is the lip at the bottom serving as reinforcement,but im going with smooth outer walls so that might be a problem. Not sure if its even possible. Those patterns have about 1/4” walls to what i was told. They where made in the 60’s

The gentleman that owns those patterns is a friend of mine,and he will be selling my final product,but he cant help,for he knows nothing about patterns. Im looking at a few castings,10 sets,maybe 20 if lucky.

If I have to,illl make it a two piece with a core box to serve as match plates. Im lost at the moments. Im learning all this on my own,you are the first person I ask for help,only because im dire need of help. Ive seen plenty videos but not many out there on pattern making…its kind of a lost art doing it by hand.

Do you glue end grain to grain with square joins,or butt them together?

Pattern making is alot harder than carpentry thats for sure.

I thank you for your time.

.


I remember the days of my apprenticeship, I felt the same. But the 1st rule of life, and patternmaking is never give up.
If you need some guidance i’d Be happy to give you my 2 cents.

- Patternguy


View PimentelEng's profile

PimentelEng

22 posts in 26 days


#11 posted 09-25-2018 07:40 AM

btw. The silver pattern shown used a core box.

View PimentelEng's profile

PimentelEng

22 posts in 26 days


#12 posted 09-25-2018 07:55 AM

Another thing. Im using tightbond 3. What glue would you recomend for such intricate jobs? I plant to coat my patterns with automotive spray can high build primer and a final coat of gloss paint

View John Smith's profile

John Smith

1374 posts in 309 days


#13 posted 09-25-2018 04:38 PM

well, first hurdle in your way is that the original valve covers are stamped
out of steel in a press in a factory. probably not cast aluminum.

I would ask to borrow the gentleman’s samples and make a urethane and plaster of paris
mold for the top parts of each and return them to him in the same condition (or better).
this will relieve you of the tremendous frustrations of making a wood pattern.
after a couple of weeks of drying, seal the plaster and make a fiberglass plug
to work with. 99.9% of your fine detailing work will be on the outside of the model.
with a plaster copy, all that work will be done for you already. including that little
“flare” at the base of the cover that will give you fits trying to reproduce.
then, all you have to do is spend some time making the internal plug, which will
give you the thickness you need for the finished product.
reinforced fiberglass will be just as strong and sturdy as wood and can be cast
over and over without any deformations.
once you have the “winner” that will sell to the public, make a set of aluminum
patterns for all your future castings.
there are many good books on the market about sand casting and pattern making.
if you are new to the two-part patterns, it would be in your best interest to pick one up.
it will certainly help calm the frustration level you are about to inter into.
please keep us posted on your progress – perhaps start a new thread in your projects sections.

Urethane and Plaster Mold:
first step is to coat the original item with a rubber silicone/urethane coating, maybe a 1/4” thick.
after that cures, the plaster of paris jacket is molded over that with burlap to reinforce it.
when the plaster fully cures, it is lifted off of the silicone mold, then the silicone coat is removed.
allow the plaster to fully cure, probably a few days in a warm, dry place.
then when you are ready to make the fiberglass casting, put the rubber mold inside the plaster
casting – it will fit like a glove and hold the rubber in the same original position as when you
first cast it from the original part.
once you have the fiberglass replica made, you can build up the thickness you need on the inside.
plus – make any custom additions or alterations to the outside design.
some of these casting companies are so precise, they can reproduce an eyelash that may have
dropped into the paint on your finish coat. so your pattern must be as perfect and blemish free
as you can get it.

.

.

-- I started out with nothing in life ~ and still have most of it left.

View PimentelEng's profile

PimentelEng

22 posts in 26 days


#14 posted 09-25-2018 05:45 PM

Im not trying to reproduce it,rather make my own from my own design. Mine wont have the lip. It will be wider and taller with no fins..a whole different patern,but for the same engine. I have the stock steel covers for reference along with head meassurements. I will use plastic wood filler for fillets and to countour certain areas. Im set on going the cope and drag,or more like core and core box,match plate method. I done a few covers that way out of MDF with great results. I just hate MDF why im switching to Mahogany.


well, first hurdle in your way is that the original valve covers are stamped
out of steel in a press in a factory. probably not cast aluminum.

I would ask to borrow the gentleman s samples and make a urethane and plaster of paris
mold for the top parts of each and return them to him in the same condition (or better).
this will relieve you of the tremendous frustrations of making a wood pattern.
after a couple of weeks of drying, seal the plaster and make a fiberglass plug
to work with. 99.9% of your fine detailing work will be on the outside of the model.
with a plaster copy, all that work will be done for you already. including that little
“flare” at the base of the cover that will give you fits trying to reproduce.
then, all you have to do is spend some time making the internal plug, which will
give you the thickness you need for the finished product.
reinforced fiberglass will be just as strong and sturdy as wood and can be cast
over and over without any deformations.
once you have the “winner” that will sell to the public, make a set of aluminum
patterns for all your future castings.
there are many good books on the market about sand casting and pattern making.
if you are new to the two-part patterns, it would be in your best interest to pick one up.
it will certainly help calm the frustration level you are about to inter into.
please keep us posted on your progress – perhaps start a new thread in your projects sections.

Urethane and Plaster Mold:
first step is to coat the original item with a rubber silicone/urethane coating, maybe a 1/4” thick.
after that cures, the plaster of paris jacket is molded over that with burlap to reinforce it.
when the plaster fully cures, it is lifted off of the silicone mold, then the silicone coat is removed.
allow the plaster to fully cure, probably a few days in a warm, dry place.
then when you are ready to make the fiberglass casting, put the rubber mold inside the plaster
casting – it will fit like a glove and hold the rubber in the same original position as when you
first cast it from the original part.
once you have the fiberglass replica made, you can build up the thickness you need on the inside.
plus – make any custom additions or alterations to the outside design.
some of these casting companies are so precise, they can reproduce an eyelash that may have
dropped into the paint on your finish coat. so your pattern must be as perfect and blemish free
as you can get it.

.

.

- John Smith


View John Smith's profile

John Smith

1374 posts in 309 days


#15 posted 09-25-2018 06:00 PM

ah so, gotcha !
have you ever worked with High Density Urethane (HDU) ??
it is a little less as hard as MDF and very tool friendly and easy to carve.
auto putty such as Bondo readily sticks to it for your details.
sounds like a very interesting project and hope to follow your progress.

-- I started out with nothing in life ~ and still have most of it left.

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