Eliminating base warp....a guide.
Posted: Tue Jan 26, 2021 11:13 am
Short story is I’ve been building skis for a decade now. Over the years I’ve had issues with base warp. Much of which was solved early on. However intermittently this creeps back in. Below you’ll see what I’ve done to solve this issue in my process. This info is scattered about in the text of this site so I decided to put my thoughts in one spot.
1. Warm you base material. UHMWPE base has a “grain” and a thermal memory to how it was rolled from the extruder. Use your heat blanket to warm the base to at least 120 deg F on a flat surface. Placing some flat weight on top like a piece of mdf also helps. Heat it for at least 15 min and allow it to cool to room temp before cutting. This will remove any thermal memory or curl from being on the roll and give you a better result. Allowing it to cool to room temp is also important so there can be no movement of the material after cutting.
2. Edge tension is a huge cause of base warp. It is absolutely imperative that your edges match your base. You should be able to hold your edges to your base with only a single clamp. If you are forcing your edge to match your base with anything more than fingertip pressure it is likely going to cause your base to warp some. If you have to force your edge into place you should be working on cleaning up your edge bending skills.
3. When using edge material that comes in a roll, you
Must take the memory out of the edge material. Straiten it manually until it sits flat on your work table and doesn’t flip on its side. You essentially have to take any bow out of the material. You can use a modified edge bender with a roller to do this. Pull it thru the rollers until the bend is taken out. Failing to take the stress out of the edge material will almost definitely cause your base to warp.
4 apply both edges at the same time to make sure any tension applied us balanced by having both edges in place.
This is my approach to base symmetry. If you have other tips please feel free to add them.
1. Warm you base material. UHMWPE base has a “grain” and a thermal memory to how it was rolled from the extruder. Use your heat blanket to warm the base to at least 120 deg F on a flat surface. Placing some flat weight on top like a piece of mdf also helps. Heat it for at least 15 min and allow it to cool to room temp before cutting. This will remove any thermal memory or curl from being on the roll and give you a better result. Allowing it to cool to room temp is also important so there can be no movement of the material after cutting.
2. Edge tension is a huge cause of base warp. It is absolutely imperative that your edges match your base. You should be able to hold your edges to your base with only a single clamp. If you are forcing your edge to match your base with anything more than fingertip pressure it is likely going to cause your base to warp some. If you have to force your edge into place you should be working on cleaning up your edge bending skills.
3. When using edge material that comes in a roll, you
Must take the memory out of the edge material. Straiten it manually until it sits flat on your work table and doesn’t flip on its side. You essentially have to take any bow out of the material. You can use a modified edge bender with a roller to do this. Pull it thru the rollers until the bend is taken out. Failing to take the stress out of the edge material will almost definitely cause your base to warp.
4 apply both edges at the same time to make sure any tension applied us balanced by having both edges in place.
This is my approach to base symmetry. If you have other tips please feel free to add them.