×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

plastic for casting pattern

plastic for casting pattern

plastic for casting pattern

(OP)
What are the best choices for a machinable plastic for use as a casting pattern, used in sand castings.?

Wood is commom, but i would like something that is a little more robust.  

www.retallickeng.com.au

Was told it couldnt be done, so
i went and did it!

RE: plastic for casting pattern

When a more robust pattern is required for sandcasting, it is common to use metal faced wood patterns or all metal patterns.

RE: plastic for casting pattern

You can use epoxy patterns. You can also use polyurethane foam(commonly thermocole) material.

If you can give a little more information it will be helpful.

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

RE: plastic for casting pattern

(OP)
The patterns are small, approx 6 in Sq, and have quite a bit of detail in them. I would like to use metal but machining them will take forever, there being done on a homebuilt cnc mill.  

I will be starting with petrobond sand molds and move onto a phenolic bonded sand if i need higher volumes.



 

www.retallickeng.com.au

Was told it couldnt be done, so
i went and did it!

RE: plastic for casting pattern

You can use as mentioned earlier,araldite patterns,they are long lasting,easy to work with and economical.

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

RE: plastic for casting pattern

(OP)
arunmao, By epoxy (araldite being a trade name) are you saying to take a mold from the orgiginal wood pattern or machining from a block?  ive never seen a solid block of epoxy.
 
My experience in epoxy is for laying up molds using carbon, kevlar and fibregrass.



 

www.retallickeng.com.au

Was told it couldnt be done, so
i went and did it!

RE: plastic for casting pattern

Yes you are right. We often cast a solid block into near desired shape and then work on it to finish. This will be faster than metal patterns.

If you need one,send along a drawing I shall get one for you free,!

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

RE: plastic for casting pattern

(OP)
Thankyou, interesting way to do it. do you use certain types of epoxy?

Are there any plastics that are also suitable?  eg, nylon, acetel, as these are easy enough to source.  I would be suprised if plastics arent used!

 

www.retallickeng.com.au

Was told it couldnt be done, so
i went and did it!

RE: plastic for casting pattern

There can be others who might have tried,but I have been working with araldite for nearly 20 years.

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

RE: plastic for casting pattern

Something like Araldite AY 103 with an appropriate hardener should be castable in blocks.
 

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources