found this thread : http://www.swaylocks.com/forums/diy-surfmat-build
but the build links in it no longer work.
how the heck do you build one of these things?
any have step by step processes, tools list, etc?
please school me!
looks interesting. thanks.
Here’s some info on mat pressure and then I’ll do a step by step…
Ive never seen anyone measure the pressure inside a mat before and i think it will help refine the essence of better design as well as being food for thought for us all.
Ok, here’s the pressure gauge, i work in the operating theatres of a hospital and this is used to measure subtle changes in pressure, its a very sensitive guage thats used for critical assessment. I wouldn’t know where you could find a more sensitive gauge…PIC 1 below.
Even if you speak into the inlet port it registers an increase. The scale is cms of H2O raised, most likely inside a glass tube.
So, the first test is an almost empty mat that folds onto itself…
PIC 2
It registered zero.
Next is a 90 degree mat…
PIC 3
It registered just under 2.
PIC 4
Next is a totally max full mat, as hard as I could inflate it.
PIC 5
It registered a 30.
. PIC 6
So already its quite interesting that until a mat is fully inflated the internal pressure hovers around zero.
Then a 60 kg rider on the full mat. The full mat started at 30 and the 60 kg rider ups the pressure by 20 units to 50.
PIC 7
Then an 80 kg rider on the full mat. It registered a 60. So an 80 kg rider adds 30 units to the full mat.
PIC 8
Then a 60 kg rider on the full mat. The full mat started at 30 and the 60 kg rider ups the pressure by 20 units to 50.
Then an 80 kg rider on the full mat. It registered a 60. So an 80 kg rider adds 30 units to the full mat.
The next test was to try the popular “90 degree mat” (that registers a 2) and test with the 60 and 80 kg riders…
The 60 kg rider registered a 20.
And the 80 kg rider registered a 30.
Here’s my thoughts…
- Until a mat is fully inflated its internal pressure lingers around zero, especially in the range where we like to have it.
2.Even with minimal air in it, its always going to hit at least 20 when you’re riding.
3.The weight of a rider makes the greatest increase in pressure.
-
While we don’t like to use a fully inflated mat, the riders weight takes the ‘riding pressure’ up near the level of a fully inflated mat.
-
An 80 kg rider on a 90 degree mat registers the same pressure as a fully inflated mat on its own, so when you’re riding an empty mat its not a supple mat at all.
-
it seems likely that its more important to have the ‘riding pressure’ under a certain level, maybe 30-40 and that can only be achieved by starting with an almost empty mat.
People have asked but the pressure wouldn’t change if the mat was on wood, carpet, sand or water.
pretty sweet. are you sewing or is it all welding?
how do you make them?
How did you figure it out?
Your question 1 no doubt has a simple answer, question 2 may be revealed by SF, question 3 is way more complex. The answer is partly lurking in Surffoil’s response to determining pressure inisde a mat.
Bob
Question 1.
Who sews a surfmat ?, it’s all glueing for me. The commercial guys use heat welding that involves a fixed metal heated frame that holds the material pieces together for a particular time at a particular temperature. I prefer glueing because I can make any shape not just the shapes dictated by metal frames.
Question 2.
It’s not hard, obviously mats have two panels for the top and bottom surfaces that are the same size. And there’s a few long rectangular material panels that make the internal I beams.
And a plastic valve for inflation.
You can make a complete mat in a day if you’re organised so let’s start with a table that’s big enough to accommodate a mat and has room for all the bits that you’ll need to have on hand. Without a quiet place to focus and create, you’ll never capture the precision to do it properly.
Plenty of light, ventilation and ‘elbow room’ to get the job done will make it a whole lot easier !
1 - can you explain where you get your material and what it is exactly?
2 - Also, how do you apply an even clamp along the whole glue line around the entire mat?
3 - Can you elaborate on the internal I beams? Is that what gives the mat the pontoons? I’m talkin pontoons like seen here :http://www.surfmats.com/classic.html
4 - Those rectangular beams don’t attach all the way from deck to hull?
thanks!
I have been researching building a mat. Every single place I look online conveniently leaves out what type of material they are making it out of. I’ll tell you one thing, I know now it’s not 200 Denier ripstop fabric. Other than that, I can’t help you.
well said monkstar. well said!
I wonder if it’s 200 denier poly coated nylon fabric. I think most of the fabrics are nylon.
you can buy that stuff here http://www.seattlefabrics.com/nylons.html#200%20D%20ctd. It’s on sale from that website, but i’m not buying any yet.
I wonder if you can glue it up with dap weldwood contact cement. I just wonder if that will hold up over time. They say Nylon is hard to glue properly because it is slick, so I guess you gotta sand the glue joint first.
surffoils, school us please!!! please answer my top 4 questions from above.
1/. The first question is not about the material but the way you’re going to join the pieces together. If you can’t get the right glue, no material will stay permanently joined, so the glue is the first step before you look for material. I use PA 5000 which is a two part glue that may be called something else in other countries. If you can get PA 5000 let me know and I’ll tell you the rest, otherwise I’m wasting hours to type and guide you to build something that’s just a casual interest for you.
2/. Dont stretch the fabric when you join them together and then use a flat metal roller to expel any air bubbles.
Check the pics I posted above.
3/. Yes the I- beams create the pontoons. As many as you like. Very easy to do. The only way to get a good looking mat, is the same way to get anything that looks perfect, lots of time and patience to get it right , the better your skills the better the mat. I measure everything out and draw out the positioning down to the millimetre. If you want to make out standing mats you have to take a lot of care.
4/. The I-beams have a gap at one or both ends depending on how quickly you want the air inside to move around.
the very first thing is to source a materials and glue supplier and then test what works with the glue you have. Follow the directions.
With material… " waterproof" isn’t what you want, it needs to be ‘AIR - proof’, some ripstops material is waterproof but is also “breathable” so when you inflate it the air escapes through thousands of tiny holes. Do a Google for local material sellers and see if they will send you samples, some sent me metres and metres, others sent me little squares, and then check the samples for suitability.
the best place to source a glue is a local inflatable boat builder, they glue the panels together so see if you can buy some glue and don’t forget to look for the importers name on the drum. My local boat guy sells the glue to me for $90 per litre… The importer sells it to me for $90 for 4 litres.
tryin to source the glue.
so hanging a rectangular I beam from the deck, inside of the mat, creates that pontoon look?
Thanks for taking the time to write that out. I appreciate it.
Monkstar, no problem at all, there’s a fair bit more to come and I’m happy to share what I know. Some things you will have to learn by actually doing it, but it’s not hard.
Poser516, the I beams are connected to both the top and bottom sides of the mat, when the mat is inflated the I beams stop the mat from blowing up into a sphere, the I beams can also put rocker and concave into a mat…
It took me months to find the right glue, the PA5000 is what the inflatable boat guys here use to make rescue boats and life rafts, so it is a professional product, so use it properly and its magic. The glue area needs to be cleaned / primed first with one product, then a thin and even layer of glue carefully applied to both sections to be joined and left to dry. Then apply the glue to both surfaces again and then bring them together, accurately, evenly without stretch, and then use a roller to expel any air bubbles without moving the fabric. If you can master this technique, you can make any shape you like. The beauty of using glue is exactly that, you can make any shape, however if you use a heat welding machine then you can only make the shapes of the heat welding machine like straights and 90 degrees corners.
Look closer at the pics above, there’s a swallow tail with a pulled in nose and a wide point at half way, you can’t get that with a heat welding setup.
thanks surffoils.
Do you ever use thermoplastic polyurethane coated nylon?
Will that glue stick to that?
How do you tell if a material is “airproof” once you get the material sample in the mail?
Yes
yes
if you get a small piece, see if you can suck air thru it.
If you get a big piece, blow it up like a balloon, twist the opening shut and submerge it in a bucket of water. Squeeze the balloon and it will fizz with thousands of air bubbles.
Lots of materials are labelled " waterproof" but aren’t suitable. In the end you have to check each sample. I get my material from a place called Bainbridge International, it’s about 200 metres away and they supply material for sailing, weatherproofing vinyl, inflatable jumping castles, all colours all weights, about $10 a metre length by 2metres wide.
Are you in Australia?
A mat should cost about $20 to make.
good advice surfoils, good advice.
Do your mats hold up over time or do the glue joints fail?
i’m in california.
What do you use for your air vent?
man, i can’t find that PA5000 anywhere on the interweb. how can it not be on the INTERWEB?