Thread: To Build A Ski Press...
02-11-2009, 11:00 PM #1
To Build A Ski Press...
Any of you ever build a pneumatic press like this one:
if so can you touch on the cost, and how it worked out for you. what did you like, and not like. what would you improve about it.
thanks!1 WIDE Ski
'and don't worry its clean, because I never get laid anyways.' - leroy jenkins
02-11-2009, 11:27 PM #2
I hear this kid named iggyskier did one...
but I can touch up the basics for you:
Cost: more then you think; both in time and money.
How it worked: not as well as you think.
Did like: Less then you think
Didn't Like: More then you think
02-11-2009, 11:58 PM #3
My suggestion would be go to grafsnowboards.com and skibuilders.com and check out the forums. Lots of people are building presses these days and there is a huge amount of variation in them. Some people are going all out for a more production quality press, while others are finding they can get by with a press frame made from just cloth. A lot of people vaccum bag their skis, too.
Anyway, I build my using steel tubing with the hopes of getting something that was production capable, just on a bit of a smaller scale.
Everything was drilled. I will say, the legs for this press were way too complicated and if I could do it again, I would simplify them a lot.
Just some of the bolts used. I think there was over 150 total, ranging between 2.5" and 7", some going thru 3 layers of steel over 5 inches. I said it was over-complicated....
Mostly done with the frame - still several pieces to add to the top of the press.
PID controller - luckily not wired by me or I probably would have killed myself
I used an aluminum cat track, MDF molds, CNC'ed tip sections, top mold is just 2x4, and fire hose.
aluminum cassettes for layup
Did it work well? You tell me
Quick answer to your questions...
Cost: Depends. You could build one for $200 or $2000. Depends what you want to do.
How it worked: See above. I was basically able to press skis non-stop for as long as I could stay awake, sometimes pressing 15+ skis in a day.
Did like: Worked well really well. OVERBUILD. It could very well kill you if you make the frame too weak. Heat is your friend. If you can afford it, a PID controlled heat blanket is very, very worth it.
Didn't Like: Only pressing one ski at a time, only have the power to support one heat blanket, and way to complicated in the legs.
Improve: My next press will be similar, but.....
- Double Bay, Double wide so I can conceivibly press 4 skis at once
- Heat Blanket top and bottom - cut pressing time in half
- Welded. Drilling is great if you are worrying about moving the press, but welding is so much faster. It took me MONTHS of work to build this press. I suspect once we have the steel and the equipment to weld it and get everything in place (including something to lift the 400lbs beams 6 feet in the air) we will be able to make our next press frame in a couple of days.
- Simple legs - next press will probably just use thick welded steel channel and will be fine.
- Press will be 1' longer. Mine was just under 8' and when pressing 191cm skis (true length tip to tail) it was a tight fit and involved a bit of tweaking to get functioning properly.
Hope that helped. If you have any questions let me know. I would basically say, overbuild, include heat, and increase the time you think it will take and the money you think it will require a lot and you have a good picture of what lies ahead.
Last edited by iggyskier; 02-12-2009 at 02:00 PM.
02-12-2009, 09:47 AM #4
^^^ every time I see that press I'm impressed
That frame could be dropped off a building and be fine.You're gonna stand there, owning a fireworks stand, and tell me you don't have no whistling bungholes, no spleen spliters, whisker biscuits, honkey lighters, hoosker doos, hoosker donts, cherry bombs, nipsy daisers, with or without the scooter stick, or one single whistling kitty chaser?
02-12-2009, 10:11 AM #5
unreal, how did you do the designs for the top sheets? are you producing skis for people to buy? do you remember the total cost of the build? the materials? Sorry for all the questions, it just mesmorizes mealpine-live.com
02-12-2009, 10:27 AM #6
iggyskier is my hero. I want a ski press in my garage.
First I need a garage....
02-12-2009, 10:49 AM #7
HA! I weld frames and shit like that for a living and that is an overbuild if I've ever seen one.
02-12-2009, 11:36 AM #8
Not ripping, just dropping a bit of health advice so do whatever you want.
This press will work... But, safety is a big issue and it certainly isn't (read: is not) overbuilt as a chain is as strong as it's weakest link (I'll come back to this). At the very least it needs to be welded. You do what you choose, but I would be remissed if I didn't say anything and someone got hurt. This is only advise and what you do is your choice.
This is a simply supported structure and improperly supported at that. Before you go out and start drawing up plans for your press first you will need to analyze the structure. Once you start crunching numbers you will see that there is an increadible amount of energy being stored in that press at even "low" pressing pressures of 50psi (average pressing pressure is 70-80psi). PSI stands for Pounds per Square Inch, so calculate the area (in^2) of your table and MULTIPLY that by 50. That number is the number of pounds being supported by your joints on only one half of the structure.
OK there are a bunch of bolts at the bottom (better). But only 2 for each joint at the top (remember the weak link comment)? You are just asking for it. All that force you calculated earlier is being applied in shear across those little bolts... NOT safe. Even if just one of those bolts fail and the rest of the structure manages to hold it would be dangerous because those bolts don't just fall off, and they don't fail slowly.
Would more bolts help? Yes, but a structure like this shouldn't be bolted together.
I've seen these things made from wood, so yes it can be done. Will this press work? Certainly it will. Are making a cheap set of skis worth endangering your life, or the life of people around you? Do it right, and don't do it until you can answer the questions about the structure yourself or at the very least understand the explanation given to you about it. Because this ain't monkey nuts, this is a real tool with the potential for catastrophic consequences. And, if you're going to do it, do it right.
[/EHS Rant]... And back to orthodontia.
EDIT: This is looking at iggy's press, but I know the press you liked too.
Last edited by RaccoonFace; 02-12-2009 at 11:59 AM.TELL YOUR BOOBS TO QUIT STARING AT MY EYES!!!1!
Here, I'll help you out:
02-12-2009, 12:05 PM #9
35 ksi 3/4" Bolt is good for 15,462.52 lbs.
11520/1546 2= 74.5% of working strength.
This is just the direct shear calculation. I'm a little busy to stab at the moment calc, but he's more than likely fine.
And I see nothing wrong with how the press is supported. There is no live horizontal loading, and the double bolts give stability. Perhaps you can elaborate.
Or does the airplane not take off?Fat fuck bubbas are not erosion.
02-12-2009, 12:09 PM #10
so yeah, again, a big kudos to you.
02-12-2009, 12:16 PM #11
The working being done holding the press cavity together for the most part is done by the 32 0.5" Grade 8 bolts per side..
This definitely isn't the most optimal design and in reality, the main supports should be on the outside side of the beams, not the inside, so that the whole beam provides support. I added the top and bottom cross sections to add just a bit more support.
As far as bolting versus welding, welding is the superior method, as long as the welder does a good job. I have seen some scary welding jobs recently. For my purposes, I knew this press would be needed to be moved around and there is no way I could afford to move a 2,000 welding ski press around. Plus I cannot weld and could not afford a welder. So it was bolted. And it saved me a lot of hassle as it was moved three different times.
Last edited by iggyskier; 02-13-2009 at 05:01 AM.
02-12-2009, 01:31 PM #12
02-12-2009, 01:37 PM #13
02-12-2009, 04:44 PM #14
Press cavity is 84" long, 10" wide. So 84" x 10" x 2 = 1680 in^2.
I pressed at 70 psi.
So 70 * 1680 = 117,600.
Each joint there was (8) grade 8 bolts. Tension capacity = 22674
so 8 bolts x 22674/bolt = 181,392. As was stated in the next page, there are other variables altering this which would lower this capacity, but I do not know how to calculate for them, so for the sake of just having something....
117,600/181,392 = 64.8% of the working strength @ 70 psi.
Last edited by iggyskier; 02-13-2009 at 05:04 AM.
02-12-2009, 05:22 PM #15
Working hard to make these available for next season, but not the easiest time to fund a start up.
Total cost of the build, tools, materials? A lot. I don't even want to get into it, but it was about 9-10 times what I initially expected.
If you haven't seen it, check this thread out. If you still have any questions, let me know.
Originally Posted by flyby
I think it is definitely easier for me to sort of put everything on the line at 22 than it would be say at 25-26. If it fails, I will have at least learned a lot. But is isn't gonna fail .
02-12-2009, 05:37 PM #16
Iggy, the failure point that I see is the connection of your beams to the legs, unless that is a slotted connection. Unless there is something that I am missing, I do not see a catastrophic failure path for your press.
HOWEVER, I do see a major design issue with the red press. The 'spacer' I beam is turned in the weakest possible direction, and will see the largest moment of the system. Bad, but it will simply bend the hell out of the press, not kill anyone.Fat fuck bubbas are not erosion.
02-12-2009, 06:12 PM #17
iggyskier: that is a truly inspiring batch of photos. I wish you the very best fortune getting your financing together and living your dreams in the coming seasons.
*If your thesis is just that welded joints are "safer" than bolted ones, I hope you don't like flying.If you're a relatively moral, ethical person, there's no inherent drive to kiss ass and beg for forgiveness and promise to never do it again, which is what mostly goes on in church. -YetiMan
02-12-2009, 06:27 PM #18
So I definitely did not feel comfortable welding my first press, nor will I personally feel comfortable welding the second press. It will be professionally welding. Definitely not taking any chances. I actually am going to try and learn to do it when sam and I build some custom ski racks that I have drawn up.
To anyone considering building, I think I should add.....go slow learning power tools. I had never used a table saw, band saw, router, router table, edge sander, etc, etc, until I started this. And if you fuck up around those tools, they will make you pay. I still have all 10 fingers and am now pretty good on all the tools I use in the shop. But that level of attention needs to be constant because, hey....everyone likes all 10 fingers . Definitely had a few close calls with kick back and such to quickly learn to pay attention.
And again, thanks for the stoke. Hopefully you can take a pair of our skis out sometime and see what you think .
Last edited by iggyskier; 02-12-2009 at 06:41 PM.
02-12-2009, 06:40 PM #19
This is a pretty sweet thread. I never actually took the time to look up what a "ski press" entailed - I really had no idea of what the process involves. For some reason I always assumed a mechanical press (think license plates...). This is actually no joke at all. Interesting to see what these look like and the concepts behind it. Good luck Iggy.
Side bar - what do the bulk manufacturers use? Larger versions with a ton of presses going? I assume they can also expend the $$$ to get a fully machined press frame (meaning solid, minimal welds - basically made of out a solid die).
Edit: Don't worry - I have no intent of building one of these!
Last edited by Unfrozen Caveman Lawyer; 02-12-2009 at 06:42 PM.
02-12-2009, 07:13 PM #20
Really, though, the concept is the same. Heat and pressure.
I can add what photos I can quickly grab online....some are personal, some are factory.
Praxis - folsom is similar
PMgear Press - Folsom and Praxis are similar in that they are a clamshell design, allowing them to open the press. making getting the ski in there nice and easy
Older skibuilders press
py screen capture of burton press
As I said, though, they really are all the same. Probably the most important factor is having perfect molds. Without them, there really is not point.
If done right, a small press is just as capable as the larger presses. What IS harder for the smaller companies, though, and doesn't matter much because of how most construct their skis, are things like cap construction or something that was 3-D on the topsheet.
I got to tour the K2 prototype factory in seattle and not only did they have a CNC mill that was larger than my entire shop (shack) but some really complicated cassettes.
Anyway, there is a bunch of presses. I am sure anyone who has considered making them has seen most already.
I know I cannot wait to get our new one up and running.
Last edited by iggyskier; 02-13-2009 at 05:03 AM.
02-12-2009, 07:25 PM #21
Iggy - thanks for the pics. Pretty sweet. The Stockli press is basically what I was envisioning at a bulk company.
02-12-2009, 07:33 PM #22
02-12-2009, 07:37 PM #23
02-12-2009, 07:39 PM #24
02-12-2009, 08:18 PM #25
I don't think you should be using the sheer strength for the calculation! From your pictures, I think you want to use the tensile strength. But it turns out that the sheer strength of those bolts is about 75% of the tensile strength.
Technically you also need to add in the preload tension of the bolts (since they are actually under load from tightening the nuts). I don't know what your torque spec is, but given that the tensile strength is higher than you estimated, I think you're still just fine!
Last edited by jondrums; 02-12-2009 at 08:20 PM.