How do you know if the casting frame is straight? And how do you straighten it?

[Ironside]

Hello,

I purchased a 45x95x4800 timber which was immediately cut down and assembled into a casting frame (120x60). Already during assembly, we noticed that the wood had twisted somewhat, and we had to apply some force to make it fit nicely. Checking with the set square afterwards, the corners are correct, but when you place it on the garage floor, you can see it doesn't lie evenly. Of course, one might wonder if the floor is level, but I actually believe it is.

In an attempt to straighten the frame, I have placed a couple of bags of pellets on two of the corners, but after 2 days nothing has really changed. If you step down on one corner, the other corner lifts up.

How can you get a sense of whether the frame is straight or not? And how do you straighten the wood? Is it even possible? Maybe it doesn’t matter as long as it’s not off by several cm?

Best regards

Edit: While we're on the topic of casting molds, is it true that you can brush a thin layer of cooking oil, like rapeseed oil, on the inside of the mold to make it release easily? Or should the inside be lined with particle board made for casting?

 

[fribygg]

Oiling the mold makes it release more easily, you can use cooking oil if you want.

 

[xLnT]

You can also attach byggfolie to the form. Normally, formplyfa is used because it is smooth. But if you use byggfolie, you can use regular plywood.

 

[fribygg]

Your studs will probably work well to cast against, in the past, unplaned wood was used and it still serves its purpose today. Common planed stud wood and cooking oil as form oil will work fine.

 

[Snickarkirre]

What are you going to cast? Is it a larger casting height? You might be able to cut the rule/rules that have bent where it's worst or perhaps in the middle of the form, then straighten it with a long level or similar, and you just splice it there with a new 45x95 piece. If the rule has bent, it's impossible to get it straight again.