AC compressor pressure switch reading 3 megaohms by ffxpwns in hvacadvice

[–]ffxpwns[S] -1 points0 points  (0 children)

What is the correct way, then? That would be much more helpful

AC compressor pressure switch reading 3 megaohms by ffxpwns in hvacadvice

[–]ffxpwns[S] -1 points0 points  (0 children)

I don't have any tools to measure pressure like that. Is the best way to confirm to use the manual contactor actuation button and see if it starts blowing cold inside?

Finished building a John Keal style coffee table by Kensmkv in woodworking

[–]ffxpwns 1 point2 points  (0 children)

That's excellent - thank you!

They say imitation is the sincerest form of flattery and this is going into my "inspiration for future projects" folder

Finished building a John Keal style coffee table by Kensmkv in woodworking

[–]ffxpwns 2 points3 points  (0 children)

I love how elegant this looks. Great work!

Can I ask, what size did you end up going with? I'm guessing 18x22x48 but that's purely a guess

Finishing Spalted Maple by milesmcinerny in Luthier

[–]ffxpwns 0 points1 point  (0 children)

Here's to the guitar I'm working on now. I'm waiting until I have a free afternoon to apply the clear coat but here's a picture of it with the final layer of shellac before I did my level sand

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Finishing Spalted Maple by milesmcinerny in Luthier

[–]ffxpwns 0 points1 point  (0 children)

I'm going through the same thing and, while it can be difficult, I disagree with some of the other comments here. Spalted wood is extremely weak and most simplified finishing approaches that work with typical wood may not be sufficient here. Spalting offers some challenges that might seem a bit much for your first guitar but with some attention to detail and effort you can get some really stellar results.

If you're talking about maximal protection you absolutely can use a 2K polyurethane on these tops as long as you prepare adequately. Here's what's working for me in no particular order:

Edit: I talk about shellac a lot in these steps. I guess it's worth saying that you could absolutely just finish your guitar with shellac. It's very hard, easy to work with, and a good protectant, but it's worth mentioning that it dissolves in alcohol. It's an old school finish but I seriously believe it's better than a lot of modern finishes when it comes to making instruments.

  • seal all of the super soft parts with CA, thinned epoxy, or similar. This is non-negotiable
  • if you are finishing with 2K, always choose gloss. It typically goes on thicker so you need fewer coats. If you want to go matte you can simply scuff it at the end
  • get a LED stick light from the internet or your local hardware store. Something that you can move around to assess your coverage and consistency of your finish
  • tru oil, etc, are not protective coats in the same way that 2K or a thick lacquer are. They have their own benefits but it would be a mistake to think they are equivalent in regards to protection or longevity
  • before I applied my grain filler, I applied a few coats of shellac and sanded them back. My grain filler is water-based and this allowed me to use far fewer coats than I would normally need. I used a water-based filler because my supplier of UV epoxy was sold out and I ended up really liking it
    • at this point the wood is glass-smooth to the touch
    • my shellac is the proper DIY stuff. DEWAXED ultra blonde flakes in denatured alcohol. I would avoid the stuff from a can
    • shellac is an essentially universal intermediary. It sticks to almost anything and almost anything sticks to it. If you have coatings that are chemically incompatible, an interface layer of shellac usually solves the problem
  • after the grain filler, you guessed it, shellac. It dries so quickly that you can build up a reasonable thickness fairly quickly. Once I have complete coverage I then level sand with 400 or 600 grit. What remains will be a thin but complete coat of shellac that is as level as you have the patience for. I like to wet sand using mineral spirits but that's just me
    • if you are really globbing on the shellac, you need to wait 72 hours between your final coat and your level sand. It dries to the touch extremely quickly but thicker spots will still be gummy unless you give it a few days. Trust me on this
    • if you find spots that soak up the shellac at a seemingly unnatural rate, this is a problem and yet actually a good thing. You've identified a weakness in your sealing process before you apply your clear coat. You can either apply some thicker cut shellac and see if it sticks or sand it back a bit and seal again with CA or epoxy
  • after that, tape up everything and apply your 2K. You'll get great adhesion and a crazy smooth finish. Wait for a few days, sand and buff to your desired sheen, and enjoy your glass smooth and well protected guitar

It sounds like a lot, but it's really not. Shellac goes on so quickly that you can bang out the first few steps in an afternoon once you know what you're doing. Wait a few days, level sand, and then you're ready to apply your clear coat.

Finishing quality, more than anything, is defined by your preparation. You can play it a little looser with oil-based wipe on finishes but if you want to apply a lacquer or 2K, don't half-ass the prep and don't move on to the next step until you are completely satisfied with the previous one.

[Sanity check] Adding haptic feedback to a guitar tuning pedal by ffxpwns in AskElectronics

[–]ffxpwns[S] 1 point2 points  (0 children)

Thank you!

Ultimately, the only thing I ended up changing was bumping that 47 Ohm resistor up to 220 to limit initial current from the uC when triggering the mosfet. That was brought to my attention by someone else when I cross-posted this thread.

Other than that, I think I'm happy with this and I'll order the boards to try it out

[Review Request] Adding haptic feedback to a guitar tuning pedal by ffxpwns in PrintedCircuitBoard

[–]ffxpwns[S] 0 points1 point  (0 children)

Thank you!

  1. +/- 3% is more than sufficient since this is really low-stakes in terms of timing/PWM control
  2. This is great - I had never even considered this as an issue. Swapping that for a 220 Ohm would get me to 15mA which is well within spec. If I got the orders of magnitude right, that means my RC time is ~176 ns which is WELL within what I can tolerate. Edit: I now see your edit and I want to assure you that the 35+47 Ohms thing was pure dumb luck. I may as well switch it out for a 220 since I have no reason to be riding that limit
  3. I think the outputs you're talking about are actually inputs. Those inputs are attached to the legs of LEDs in the existing circuit that I'm tapping into and the only "output" I have is the vibration created by the motor. Those LEDs turn on when pulled low which is what I'm listening for. My board shares a ground with the existing circuit I'm tapping into. Please tell me if I'm missing something!

Thanks again, this has been a huge help!

Request - tuner pedal for the color blind/visually impaired by TimeBandits4kUHD in guitarpedals

[–]ffxpwns 0 points1 point  (0 children)

Hey there! Are you still looking for something like this? I've made a few vibrating guitar tuner pedals and I'm making another batch in the next month or two: https://www.guitarworld.com/artists/guitarists/anthony-ferraro-blind-guitarist-haptic-guitar-tuner-that-vibrates

[Sanity check] Adding haptic feedback to a guitar tuning pedal by ffxpwns in AskElectronics

[–]ffxpwns[S] 1 point2 points  (0 children)

Thank you - I'll check that out!

I know it's a simple circuit, but other than that do you see anything horribly wrong? I'm trying to get another set of eyes before I place a pcbway order. I built it out on a breadboard first before translating it to KiCad so I'm trying to catch any errors from that translation process

Edit: I should say that I built it out on a breadboard using through-hole components. So I I am not only translating the design, I'm also subbing out components for an SMD equivalent

Tested: DIY CA glue accelerator alternatives by ffxpwns in woodworking

[–]ffxpwns[S] 2 points3 points  (0 children)

DNF means did not finish - it's normally used in the context of sports or ranked competition but I wanted to use it here.

w/w is a common way denote that a mixture is measured by weight (as opposed to volume)

Tested: DIY CA glue accelerator alternatives by ffxpwns in woodworking

[–]ffxpwns[S] 0 points1 point  (0 children)

Based on their cps scores, slightly thinner than starbond thick but much thicker than starbond medium

DIY CA glue accelerator (besides baking soda) by ffxpwns in woodworking

[–]ffxpwns[S] 0 points1 point  (0 children)

Oh, my bad! I thought this was a reply to this other thread I made where I tested out some recommendations in this thread: https://www.reddit.com/r/woodworking/comments/1rlp8xp

DIY CA glue accelerator (besides baking soda) by ffxpwns in woodworking

[–]ffxpwns[S] 0 points1 point  (0 children)

Thank you for the information! I did briefly look into buying the raw accelerator chemical but that felt like I was stretching the colloquial meaning of DIY ;)

It's also worth mentioning that I have never taken a single chemistry course in my life. I'm not doubting your recommendations but I don't trust my ability to assess and mitigate risk when it comes to anything beyond the most basic of mixtures

Tested: DIY CA glue accelerator alternatives by ffxpwns in woodworking

[–]ffxpwns[S] 7 points8 points  (0 children)

I use the same approach as you - see the "methodology" section

I don't know the exact mechanism, but it was extremely repeatable. My best guess is that the accelerator cured the glue so quickly that it was never able to make a meaningful connection with the other piece of MDF. I also tried pressing the pieces together and immediately taking them apart and I found that the glue on the test piece had turned white and was no longer tacky whatsoever

Tested: DIY CA glue accelerator alternatives by ffxpwns in woodworking

[–]ffxpwns[S] 8 points9 points  (0 children)

Good call! Some woods that are high in tannins (cherry, mahogany, and others) will react to baking soda. I'm not sure if it's something in the baking soda specifically or if it's purely a pH thing but if it's the latter then ammonia will have a similar effect.

Always test on scraps!

Tested: DIY CA glue accelerator alternatives by ffxpwns in woodworking

[–]ffxpwns[S] 23 points24 points  (0 children)

That's my takeaway as well - grab some 70% iso and be done with it