Sylvano ZeroSmogISH fume extractor - how to measure rosin fumes level? - Page 1
Forum section: electronics / projects

author: sylvanoMTL
author_rank: Contributor
timestamp: July 22, 2024, 05:09:35 pm
content: Good afternoon,I am starting a project of a fume extractor that is based on the Weller zero smog.I watched Dave's video couple of weeks ago and noted the very simple design from Weller: a filter, a centrifugal fan, some circuitry and an ugly plastic box.During the teardown, i noted the reference of the centrifugal fan : EBM papst RG128. It seemed discontinued but I was able to find one on ebay running 24VDC. in fact it is sold as a Boiler fan, and the one i have apparantly was sold to Vaillant, there is an additional flange on it. I paid it £25, £30 with shipping.Not for the filter, I am decided to use one of these:https://www.filtersdirect.uk/product/h13-hepa-filter-150mm-deep-standard-capacity-wood-case/pretty similar to Weller I guess. I may also add some carbon pellets. they does not cost much.Electronic will be: Main to DC, fan controller, and some smart measurement sensor link to a esp32.Box: a lovely wooden box that would match my office furnitureI am still scratching my head on doing things a bit smarter than the commercial solutions: I would like to measure the efficiency of the filter. To do so, I am thinking of these two solutions:1) measure the rosin fume level at the inlet and outlet of the filter, and compute the difference2) measure the rosin fume level at the outlet of the filter over time, so that I can estimate when it is time to change the filter.Does anyone know how to measure the rosin fume level?Sylvain

author: BrokenYugo
author_rank: Super Contributor
timestamp: July 22, 2024, 06:05:23 pm
content: Maybe a pair of dust sensors?If filter life monitoring is your primary concern looking at pressure ahead of the filter might be a better approach.

author: sylvanoMTL
author_rank: Contributor
timestamp: August 23, 2024, 08:48:40 am
content: OK, with some little time I have now selected a SGP41, which would be placed in the same cavity of the fan exhaust.Fan will be controlled with a EMC2101. Still need to have a knob and a LCD screen to source.Filter has been now delivered, quite expensive H13 and as I expected no activated carbon filter. (nice packaging with some inner foam that could be use for sound dampening)I have had the chance to see the top of a Weller filter at work and it has a fluffy cotton cloth as a first layer:https://uk.farnell.com/weller/t0053642199/filter-disc-pk3/dp/841420?gross_price=true&srsltid=AfmBOortk9qaPuJdYWs3kMR-f8F3MZYkVC9X8SDu6GuLLI7bTvGpKf-YP2IIt seems a glass fibre material. Does anyone know how to source it in the UK?

author: DaJMasta
author_rank: Super Contributor
timestamp: August 23, 2024, 04:59:36 pm
content: You may have to deep dive to see what chemicals are being aerosolized in soldering and what sensors are actually rated to sense them, but I would say that your choice sounds like a reasonable one to me, though the datasheet says it's tested with ethanol vapor. If you go the particulate sensor route, google says 0.1-1 micron particle sizes, and a laser based particle count sensor would probably also do the job.As for the filter, you're probably looking at a polyester prefilter for larger particles. You should be able to find sheets of it cut for all sorts of kinds and brands of filter, as well as in rolls of filter batting or similar. If you have decided on a form factor (or are willing to adapt your design), you could find a cheap standard sized HEPA filter cartridge (similar to what's used in countertop air purifiers or HVAC systems), and just use one of those pleated fabric filters instead. So long as the material has a particle size rating to your liking, I don't know if there's a big difference between the batting style and the pleated paper filters (maybe the thicker ones can saturate with more particulate, but unless it's breathing a few packs a day, it will need to be changed well before then.)The Weller filters say they are half carbon half Puratex (proprietary resin chemical absorber), and its these active portions of the filter that are probably the most important for soldering fumes - they bind to the smaller particulates and break them down or trap them, the sort of particles mechanical filtration doesn't catch.

author: dustooff
author_rank: Contributor
timestamp: August 24, 2024, 09:23:37 am
content: A DIY fume filtering /extraction system is also on my horizon, previously my workbench was close to a window, lots of fresh air movement. Now with additional use of flux paste I'm finding using a filter in my best interest.Does the burnt rosin from standard flux core solder contain any VOC's ?I'm assuming flux pastes must contain some additional chemicals.From what I have seen VOC, NOx (gas) sensors have some lag, and also require some time to clear.I obtained one of these, accurate it may not be, but good as a guide.https://vi.aliexpress.com/item/1005006437119150.htmlGenerally found not necessary to leave it on once I have an understanding of what reaction it has to chemicals used.Makes me more aware of how much impact chemical use in the workshop causes.rosin as described byhttps://echa.europa.eu/substance-information/-/substanceinfo/100.029.518

author: sylvanoMTL
author_rank: Contributor
timestamp: September 03, 2024, 12:22:52 pm
content: I have a Sensirion SEN55 in my hands and was able to read data. It is ,ore expensive £35 than the SGP41 but it does the particulate size. I am still looking at the metrics, and maybe you know better than me which size of particulate matter I should monitor for solder fume.I have also found this page that contains a nice picture from Weller FT:https://eleshop.eu/knowledgebase/smoke-extraction/A M5 pre-filter seems ok (easier and cheaper to source)I have a HEPA H13 alreadyI am currently designing the carbon active container. I guess it is sensible to have the possibility to replace the activated carbons. Hepa H13 filer can be clean with compressed air (outside), and I guess they shoudl last relatively long for DIY purpose.

author: sylvanoMTL
author_rank: Contributor
timestamp: September 03, 2024, 12:29:49 pm
content: Yes rosin fume is categorised as the main respiratory health and safety hasard.The problem I see with off the shelf systems are:* There is no much filter monitoring (you trust your system and replace the filter at a fixed date)* Filters have propriatery shape/material* Filters are very expensive* Dependency on obsolescence in the future years* You need to change the whole filter, while it seems that you can clean the prefilter and Hepa filter and replace the activated carbons* There are noisy, due to the plastic box/ metal box construction.* They are ugly.on that last two points, I am plannning to upcycle veneer plywood shelf from a neighboor, and add mass by adding bituminen viscoelastic tiles inside the enclorsure (Teroson).